any post-la resistance mp strat guides?

[jevry]

hi y'all, i want to try and learn not to get powned as the soviets in the current la resistance patch. but most if not all guides are very outdated.
anyone has good advice how to do mp competently?
things i have learned myself:
-AA support companies >>> CAS (due to a bug appearently)
-no air russia = best russia, even in the most recent patch
-despite it seeming cool, putting heavy TD in your frontline divisions to invalidate the germany player using tanks at all is not a very good idea, and makes you very vulnerable as it makes churning out enough divisions to prevent alternative attack routes impossible. (i got shanked by a rogue turkey player last time because of my lack of divisions)
additionally even 88 piercing is not enough to stop a 15/5 setup medium tank division. so more dedicated AT is required.
-getting dlc, despite not giving any actual boons in mps hosted by dlc owners, helps getting used to and effectively use the items they bring (LOVING the spearhead button thing in SP)
-building infrastructure before you can switch to war eco as soviets is a decent idea. don't build it however afterwards, 2 extra infrastructure on 5 infrastructure base states only pays off once you can fit ~7-8 extra factories on them. yes it means you take less attrition. but also it means the germans take less attrition. so why not just use supply companies?
-aiming for 200 CIC by 1941 as soviets is too much, despite what the guides tell you. it puts you at a severe MIC production day disadvantage i think 170-180 including the ones gained from trade oughta be the sweet spot. germany only gets up to ~160 CIC by 1941 anyways so it should be fine
- i've heard (unconfirmed) that due to a recent nerf 10 infantry divisions >> 7/2 infatry/arty divisions.
-flexible industry for that factory retention is just good... yeah you lose some production in the long run but in the short run not losing 80% of your production speed when you unlock new guns (and then working 2 years to reduce that penalty by half only to unlock new guns again) is WAY better imo.

things i'm still trying to figure out:
-how do you prevent strat german bombers effectively? assuming the usa player doesn't want to lend lease you any fighters. (because ofcourse he doesn't want to, why would he...)
put ~4 factories on fighters atgamestart and put them above your factories?
-if spamming heavy TD isn't a viable strategy, what is the go to strat to prevent armored spearhead breaktroughs? just micro manage a fast response armored battallion of your own?
any alternatives for a terrible micro-manager that doesn't include entering the war in 1941 with only 150 20w divisions?
-not important for USSR, but how do you set up ships effectively?i so far learned ship armor is probably a all-or-nothing concept, just don't use it at all unless you plan to prevent penetrations fully.
-what support companies to use? if you use all 5 you can seriously expect nearly a 40-50% increase in CIC cost per division, it's actually ridiculous how much damage careless support company injection does. (yes i know it contradicts my 'use supply companies, not infrastructure' argument)

edit: decided to add some updates to things i've learned so far.
-as ussr, a good argument to pick deep battle over mass mob is the direct decrease in supply consumption of -20%, this means you can spam infantry more effectively without having to use support companies. you need to be able to churn out infantry at your hearts desire because else you risk germany opening up new fronts you have no soldiers for to hold (for example finland, turkey, sneaky naval invasions). additionally it buffs tanks better than mass mob, and since your infantry is now less effective you need good tanks to counter the german tank attacks and/or distract them with attacks of your own.
-this also means you want positive heroism and save your tank genius during the great purge. keep in mind this means your best field marshall will die and you need a replacement, just promote one of your best generals instead, he will likely be better anyways so it shouldn't be a large issue.
-to save sanity, put your 400 infantry spam under 1 nameless commander and assign him to your field marshall. otherwise you need 20 more generals and 5 more field marshalls, all for ~5% more effectiveness at combat. not worth the hassle NGL.
-as ussr, put ~2-3 factories on fighters and consider switching the production to heavy fighter I. they are the most effective at countering german bombers.
do not use any more factories on planes, instead put ~3-5 factories on AA guns to put in your divisions as support companies. this is mroe effective than countering the german airforce. you can start your own actual airforce production in ~42-43, when you reach the point you aren't sure anymore where to put all your 200+ military factories.
-altough you will lack air superiority, with some luck germany will be held back in air force as well due to the allies and oil shortages. this is probably part of the reason why no air russia is a strategy. however still you will have yellow air at best most of the time, heavy tanks, while more effective, are slow. enemy air superiority slows divisions down as well. for this reason, consider using medium tanks instead, that way your armored divisions can actually keep up with the enemy infantry. additionally since as the ussr you are on the defensive, you want extra speed on your attack divisions so you can counter the german player's breaktrough attempts.
-don't forget to man the stalin line and don't build any factories in front of it. destroy the fuel depot in kiev. (stalin line is basically a river troughout russia, look it up to see where it is exactly.) just let the germans have any land in front of the stalin line. this strat is usefull for 2 reasons: 1 germany has to push you accros a river (very hard to do) and 2 germany has to deal with yoru angry russian partisans (not a large deal tbh but any help you can get is always appreciated right?)
3: teh stalin line has a kink down south near romania. if you can beat the german tanks this is great encirclement ground. carefull, it's also and excellent place for the germans to encircle you.

focus tree tips:
- as the ussr, delay the great purge for as long as possible, you can do about 9-10 other focuses before you do the great purge. use this time to complete the industry tree and the tech slot from positive heroism. afterwards also consider getting the random infrastructure from the middle tree. only then do the great purge.
this works outfor a couple of reasons. 1: it means you get more and better volunteers during the SCW, during which you will have a fierce brawl with the german volunteers. 2: after you do the great purge you want to manually justify on latvia to complete a quick war and move on to lessons of war. the reason why the great purge modifier is EXTRA bad is the -20% in factory output. you want to get rid of the debuff asap and manually justifying is the best way to do this.
if your server doesn't allow this unjust justification in 1938 for some reason,the german player is probably forced to give you the winter war anyways so it actually works out fine.
-speaking of the SCW, disband all but 6 of your light tank divisions you start with. trust me you NEED those spare light tanks to keep your volunteers supplied troughout the SCW.
-avoid all the other 210 day focusses for as long as possible.anti-fascism leads to wargoals you get free from the non-aggression pact anyways so its completely usseless. anti-capitalistalso leads to unnessecary focus options. instead i suggest after completing lessons of war, it's relevant tech slot unlock, and the positive heroism+tech slot unlock. just switch over to continuous foci. they are more effective at helping you than the middle fcus tree anyways. (found the cpdi is still an acceptable boon and you shoudl consider grabbing it anyways.)

 

[Searry]

Massault feels very strong if your country can tank the manpower. 300 or more divs of 20w inf is very strong, lots more required for SU.
SU should go for the tank bonuses or they basically have to hope for a succesful invasion of western europe.

Forts are completely useless.

 

[jevry]

Massault feels very strong if your country can tank the manpower. 300 or more divs of 20w inf is very strong, lots more required for SU.
SU should go for the tank bonuses or they basically have to hope for a succesful invasion of western europe.

Forts are completely useless.

speaking of mass assault, deep battle or mass mob? i usually pick mass mob because i don't feel confident enough that i get to push back.(+less days of research time to complete it, meaning mroe tech in other fields)
iirc the main advantage of mass mob is the much higher recovery rate, which seems usefull to me if the german player decides to spam attack even when losing until my divisions break.
300+ 20w infantry divisions by 1941 sounds undoable unless you use no support companies, how do these spammable inf divisions look like and how do you organise them into the army? should i just put the 250 worst ones under a nameless general and use the other 4 marshall slots for tanks/mororised and good infantry?

and with tank bonusses, which ones? so far due to my testing with the silly heavy TD builds i've usually just rushed heavy TD 2 the moment germany gives me the research boost in tanks. and iirc the other avaible tank bonusses are at a cost of effective infantry.
the forts thing i've already heard stories of. something about fort buster being broken.
though i've seen a lvl10 fort in el-alamein work quite well for the guys in my regular group...

 

[Searry]

For defense mass mob. Since you'll just be defending, it is enough. The point is the reinforce rate, you just spam 20w divisions with no support companies or anything else. The point is to have so many divisions, you can keep reinforcing forever. For France, CAS are good for killing tanks while your allies deal with the air superiority etc.
I just use field marshal fronts for this kind of spam inf so the generals don't need to be great.

SU just needs to maximize the effectiveness of their tanks so they have to leave certain people alive in the purge and go for positive heroism.

If Germany goes for the typical template I think you need to trap them instead of just fighting normally, so you need to have good tank divisions to kill them.

 

[jevry]

SU just needs to maximize the effectiveness of their tanks so they have to leave certain people alive in the purge and go for positive heroism.

If Germany goes for the typical template I think you need to trap them instead of just fighting normally, so you need to have good tank divisions to kill them.

Positive heroism?! But what about the boons of the other option? Positive heroism has only 2 things going for it, better tanks and 140 days less time of focus tree because kamikaze strike and female pilots are somehow even less usefull than ant-fascist/capitalist diplomacy.

But anyways speaking of tanks, just use the 15/5 template? With medium tanks?

 

[ecpgieicg]

building infrastructure before you can switch to war eco as soviets is a decent idea. don't build it however afterwards, 2 extra infrastructure on 5 infrastructure base states only pays off once you can fit ~7-8 extra factories on them. yes it means you take less attrition. but also it means the germans take less attrition. so why not just use supply companies?

Oh no. If given the option, I would rather destroy infrastructure. It's called the lure-them-in strategy.

A competent German player should be able to push into USSR at least somewhat. Increasing infrastructure for them does not make sense.

how do you prevent strat german bombers effectively?

As in, you don't find heavy fighters effective enough?

Plus regular fighters do intercept them well. It takes nominally a similar amount of losses per kill. In reality, that's way less IC expended per IC destroyed.

In the air, you don't need special strategy. All you need is numbers. (Although I like bombing infrastructure for the lols as USSR.)

flexible industry for that factory retention is just good... yeah you lose some production in the long run but in the short run not losing 80% of your production speed when you unlock new guns (and then working 2 years to reduce that penalty by half only to unlock new guns again) is WAY better imo.

Has vanilla HOI4 rebalanced Concentrated vs Dispersed at some point? With the numbers from release, Dispersed never makes sense. The math does not work out.

not important for USSR, but how do you set up ships effectively?i so far learned ship armor is probably a all-or-nothing concept.

Ship is already an all-or-nothing concept.

As for armor, you calculate ahead of time your armor target based on the bonuses you expect to get from doctrines, plus Ironside, minus shell design bonuses. Hit 50 plus or 60 plus. Those are the benchmark piercing of certain early-game heavy guns. Though I could be remembering it wrong. Don't really play vanilla HOI4 these days. But you want to force higher investment out of your opponent with armor. If you can get armor above piercing on ships, plus good AA, a small (but modern) naval force can be quite potent against UK or US. We are talking about Germany and Japan as challengers here. The pre-requisite is coordination to control World Tension. Otherwise, by having no industry, you basically have no ships to begin with.

 

[Searry]

Positive heroism?! But what about the boons of the other option? Positive heroism has only 2 things going for it, better tanks and 140 days less time of focus tree because kamikaze strike and female pilots are somehow even less usefull than ant-fascist/capitalist diplomacy.

But anyways speaking of tanks, just use the 15/5 template? With medium tanks?

Yes, If you don't go all in with the tanks, you're stuck on defense.
That template is good.

 

[Bki]

Doesn't heavy tank make more sense given the resources you have as the USSR? Or since you can balance trade in MP so that they don't actually cost CIVs, not having much tungsten isn't actually an issue?

 

[Realpolitik_Bismarck]

“Has vanilla HOI4 rebalanced Concentrated vs Dispersed at some point? With the numbers from release, Dispersed never makes sense. The math does not work.”
I would beg a differ as dispersed adds the production retention buffs and production efficiency base increases. While it does not offer the raw preduction it does allow for faster upgrading of equipment and makes up for the raw production by stopping bombing damage and taking less time to hit 100% efficiency. Especially for small countries with few factories that cannot afford to have Them Bombed out by enemy stray bombing... mainly i use concentrated Industry when I play the US or China where either your safe from bombing and have time or you just REALLY need the raw production respectively

 

[ecpgieicg]

“Has vanilla HOI4 rebalanced Concentrated vs Dispersed at some point? With the numbers from release, Dispersed never makes sense. The math does not work.”
I would beg a differ as dispersed adds the production retention buffs and production efficiency base increases.

You are pointing to the obvious here. The whole point of the comparison is to see whether production retention is enough to counteract straight up production. And it does not. If you insist it does, please show the math.

Especially for small countries with few factories that cannot afford to have Them Bombed out by enemy stray bombing...

OP is discussing USSR mainly along with other majors.

In SP, you need to get into a strategic situation where you are able to contest air superiority. In MP, you cooperate with teammates and the same idea applies even if the fighters protecting your territories may not come from your own factories.
If you need additional bombing protection in some niche situation, you sacrifice nominal production for it. And that's outside of the Concentrated vs Dispersed calculation on production.

 

[sekelsenmat]

-AA support companies >>> CAS (due to a bug appearently)
-no air russia
-despite it seeming cool, putting heavy TD in your frontline divisions to invalidate the germany player using tanks at all is not a very good idea.....
-building infrastructure before you can switch to war eco as soviets is a decent idea. don't build it however afterwards, 2 extra infrastructure on 5 infrastructure base states only pays off once you can fit ~7-8 extra factories on them.....
-not important for USSR, but how do you set up ships effectively?i so far learned ship armor is probably a all-or-nothing concept, just don't use it at all unless you plan to prevent penetrations fully.
-what support companies to use? if you use all 5 you can seriously expect nearly a 40-50% increase in CIC cost per division, it's actually ridiculous how much damage careless support company injection does

Ship armor is not all or nothing, I think it is worth it in all frontline ships: 0.1+0.9xPiercing/Armor=damage

Also worth it to use the bonuses to get higher tier hills since they are much faster so less hit chance. Also more reliable. Fire control still decreases reliability so still useless.

Support companies are unrealistically weak, and the land AA bug was fixed but it is still unrealistically strong.

As USSR you can build infra in the few non-western states with many slots so the Germans won't use it.

 

[jevry]

As in, you don't find heavy fighters effective enough?

Plus regular fighters do intercept them well. It takes nominally a similar amount of losses per kill. In reality, that's way less IC expended per IC destroyed.

In the air, you don't need special strategy. All you need is numbers. (Although I like bombing infrastructure for the lols as USSR.)

that's a point i would like clarification on, you're saying the best counter to strat bombing is heavy fighter on intercept?
i never knew their purpose personally because i thought they would be good as bomber escorts, except there is no escort mission type and they are terrible against fighters due to poor agility.

Has vanilla HOI4 rebalanced Concentrated vs Dispersed at some point? With the numbers from release, Dispersed never makes sense. The math does not work out.

so from what i can read from skimming that link dispersed industry is generally worse during 1936-1940? but gets more acceptbale afterwards because only then the retention bonusses really start to kick in?

Ship armor is not all or nothing, I think it is worth it in all frontline ships: 0.1+0.9xPiercing/Armor=damage

Also worth it to use the bonuses to get higher tier hills since they are much faster so less hit chance. Also more reliable. Fire control still decreases reliability so still useless.

Support companies are unrealistically weak, and the land AA bug was fixed but it is still unrealistically strong.

but wait... according to that formula, 0 armor means any shot with piercing above 0 does litterally infinite damage. that formula can't possibly be right...? besides realistically speaking no armor means overpenetration for AP shells aka no damage to internal structure at all

what is 'higher tier hills'?
i'll note the reliability impact from fire control is more detrimental than the bonus dmg is a boon
so far i like focusing damage prevention tech because it instantly applies to all ships and the critical hits areextremely crippling.
sadly pdx seems to know this and all the ship techs that apply to all for free are super expensive to research

and for support companies, i need a little more context than "they are unrealistically weak"
does that mean i should put AA in the main divisions? disregard support companies as a whole? shouldn't i still use a lot of support companies on my tank divisions which are expensive already anyways? didn't recon get buffed recently?

Doesn't heavy tank make more sense given the resources you have as the USSR? Or since you can balance trade in MP so that they don't actually cost CIVs, not having much tungsten isn't actually an issue?

very good point. that is indeed a hard choice as the ussr, mainly i look at it this way:
pros of heavy tanks:
they are very tough and stronk. they will be effective at defeating player made and controlled divisions very well.
ussr has enough resources to build heavy tanks without imports, unlike medium/light tanks who will tax your CIC economy as well as your MIC industry.
cons:
they are super slow, something you don't want from your attacker division, you run a high risk getting encircled while using heavy tanks especially under enemy air superiority which, let's be real, as no air russia you defenitely will be under. and our germany players usually are the encirclement-addicts so losing some divisions is a garuanteed.
they are very expensive, meaning you can build way less tank divisions unless you compromise their size and strength.

im not sure which is the better pick.

 

[Searry]

No air is terrible. Better for the US to just LL most of the fighters.

 

[jevry]

No air is terrible. Better for the US to just LL most of the fighters.

what if you wanted [fighter planes]
but [USA] said [no].

i can afford ~3-4 factories on fighters but that's about it.
if i don't focus all my industries on non-plane stuff things dont end well

 

[sekelsenmat]

that's a point i would like clarification on, you're saying the best counter to strat bombing is heavy fighter on intercept?

The air combat formulas say that 100 Light Fighters 36 attacking 100 Heavy Bombers 36 kill on average 0.83 bombers. The same situation, but heavy fighters kill on average 1.555 bombers. So yes, according to the formula they are much more effective. But like you said, they are terrible against light fighters.

but wait... according to that formula, 0 armor means any shot with piercing above 0 does litterally infinite damage. that formula can't possibly be right...? besides realistically speaking no armor means overpenetration for AP shells aka no damage to internal structure at all


what is 'higher tier hills'?
i'll note the reliability impact from fire control is more detrimental than the bonus dmg is a boon
so far i like focusing damage prevention tech because it instantly applies to all ships and the critical hits areextremely crippling.
sadly pdx seems to know this and all the ship techs that apply to all for free are super expensive to research

I thought it was clear, but the formula above is a modifier for the damage that never goes bellow 10% and never above 100%, so no crazy cases of zero armor. The game doesn't model AP shells passing through and this only happens when the attacker chooses the wrong shells. British warships had no trouble sinking unarmoured transports in the Duisburg convoy battle.

And higher tier hulls I meant 1940 hulls for BB and CL, the stupid autocorrect changed to hills. Faster ships are less likely to be hit by guns/torpedoes in the game.

and for support companies, i need a little more context than "they are unrealistically weak"
does that mean i should put AA in the main divisions? disregard support companies as a whole? shouldn't i still use a lot of support companies on my tandivisions which are expensive already anyways? didn't recon get buffed recently?

No, support AA and Art is fine. I meant that there is a new current, for example the user "Cavalry", that thinks that the rest of support stuff is likely more detrimental then helpful due to increased casualties and decreased org. I can't say for sure this is really the "meta"

 

[jevry]

edit: crap the screenshot i had just vanished, thanks forums!
okay goodnight.

just finished this practiserun. sadly appearently expert AI does balance changes as well which means some thing sare gonna be off.
but generally i think i can achieve most what i achieved here. (the worst offending change is the nerf in division exp buffs/debuffs, also i had 20 mroe factories from trade than i expect to have in vanilla MPs)
as you can see, 400+ (20w) infantry divisions, i had about 320-340 when the war kicked off. (and yes because i can't handle 20 generals assigned to 4field marshalls to control the divisions i threw them all under one nameless commander)
i have 1 general full of light, medium and motorised. they all started as 20 width due to lack of exp but i kranked the mediums up to 40w after the war started and i suddenly had 200exp lying around.
the general i grinded in spain for the tanks i manage dto get: tank leader, adaptable, hillfighter and mountaineer on. i decided adaptable might be a good choice as it allows better performance on all terrain.
i also decided upon a second squad of 8 medium tanks to counter enemy tank movement.
tbh the tanks (especially the light ones) performed subpar against the romanian infantry i tested the tanks out against. the romanian ai was using 40w infantry for refference. i did have air superiority somehow (silly AI, letting me control the skies with only my 200 1918 early tac bombers)
i also chose deep battle instead of mass mob since we're focusing tanks more this time around. additionally mass mob gives straight up supply consumption reduction, which saves me the hassle of using factories on supply support companies. (which means moar infantry spam!!!)

ofcourse even with the slightly better ai it does not compare to a devious player prowling on frontline weaknesses. but i think this all around can work

 

[ecpgieicg]

that's a point i would like clarification on, you're saying the best counter to strat bombing is heavy fighter on intercept?
i never knew their purpose personally because i thought they would be good as bomber escorts, except there is no escort mission type and they are terrible against fighters due to poor agility.

If we rely on the formula on the wiki, which is in agreement with what devs have said so far, air attack provides the raw damage and air defense reduces damage most directly. Agility and speed do scale with agility counted again for defense.

With bombers though, bomber agility is low. So agility is out of the question. Hence heavy fighter is more effective.

When intercepting bombers, good amount of either fighters or heavy fighters will disrupt them. In order to hurt your enemy's IC, you want as many bombers shot down as possible. Only then is when we talk about heavy fighters vs fighters. Heavy fighters do more damage on bombers. Devs have mentioned in various videos like World War Wednesdays where they spoke of heavy fighters as such. Fighters will also do damage but will take losses. You will still win in IC but your fighter force can be attrited.

so from what i can read from skimming that link dispersed industry is generally worse during 1936-1940? but gets more acceptbale afterwards because only then the retention bonusses really start to kick in?

No, the author just left the post at that point. Dispersed is conclusively bad until 1940. You will need to copy the formulas and plug in the numbers for when later techs are added. My expectation is Dispersed will continue to be bad. The Dispersion techs actually do very little in helping with intention. That's why the large amount of raw output from Concentrated always wins out.

It's one of the many balancing issues in HOI4. HOI4 goes for simple multiples of 5, 10, 20 instead of actually prioritizing in-game effects. For Disperse vs Concentrated to work as intended, the raw output difference should be at most 3% per tech and probably less. The retention from Dispersed is very small -- probably by designed. Vanilla HOI4 should not allow techs that negates the drop in production when upgrading. That part I support.

but wait... according to that formula, 0 armor means any shot with piercing above 0 does litterally infinite damage. that formula can't possibly be right...? besides realistically speaking no armor means overpenetration for AP shells aka no damage to internal structure at all

There is the variable in defines called COMBAT_ARMOR_PIERCING_DAMAGE_REDUCTION. So at least you can guess that ship armor reduce damage as a post multiplier.

Ship armor is not all or nothing, I think it is worth it in all frontline ships: 0.1+0.9xPiercing/Armor=damage

Where/how did you get the formula please?

 

[jevry]

There is the variable in defines called COMBAT_ARMOR_PIERCING_DAMAGE_REDUCTION. So at least you can guess that ship armor reduce damage as a post multiplier.

about that formula i have heard earlier, now keep in mind i have no clue about the exacts of the dmg calculation, but i heard that armor reduces up to 90% of the damage
but if piercing is higher than the armor the damage is still 100% effective.
so unless you have armor that at least matches enemy piercing values undermatched armor should theoretically be completely usseless and not worth the production costs.
if your armor however is higher than the piercing value, lets say its double the pierce, you reduce damage by about 50-60%.
which is a good amount, but imo not enough. especially considering that for example in heavyVSheavy engagements you will likely only have ~20% more armor than the enemy has piercing. which means you only reduce damage by 10-20%. so in the grand scheme of things it might be beneficial to instead reduce production costs of your ships by 10-20% rather than heaving the die 10-20% slower, ESPECIALLY when considering the limits imposed from the naval treaty that is in effect usually up till at least 1938. altough those limits are most impactfull on capital ships.

so i probably missed something, since well i litterally only have juggled with ship design stuff for a couple of hoours so far.
but assuming that 100% pierced armor does nothing there is an argument to be had that armor is all or nothing.

 

[sekelsenmat]

Where/how did you get the formula please?

https://www.reddit.com/r/hoi4/comments/b00nz6
I can't be 100% sure but it was discussed multiple times and I think there is a general agreement on this.

 

[ecpgieicg]

https://www.reddit.com/r/hoi4/comments/b00nz6
I can't be 100% sure but it was discussed multiple times and I think there is a general agreement on this.

Thanks for the link.

For me, being referenced several times does not mean "general agreement". And I don't really ascribe much weight to general agreement for the sake of it being a popular opinions. (By not much, I really mean none.) To me, opinions without evidence are void of value, popular or not.

I'm going to wait for description by the devs or test results on the topic.

EDIT: I should also mention that the formula makes zero sense. The formula means higher armor -> less damage reduction.

about that formula i have heard earlier, now keep in mind i have no clue about the exacts of the dmg calculation, but i heard that armor reduces up to 90% of the damage
but if piercing is higher than the armor the damage is still 100% effective.
so unless you have armor that at least matches enemy piercing values undermatched armor should theoretically be completely usseless and not worth the production costs.
if your armor however is higher than the piercing value, lets say its double the pierce, you reduce damage by about 50-60%.
which is a good amount, but imo not enough. especially considering that for example in heavyVSheavy engagements you will likely only have ~20% more armor than the enemy has piercing. which means you only reduce damage by 10-20%. so in the grand scheme of things it might be beneficial to instead reduce production costs of your ships by 10-20% rather than heaving the die 10-20% slower, ESPECIALLY when considering the limits imposed from the naval treaty that is in effect usually up till at least 1938. altough those limits are most impactfull on capital ships.

so i probably missed something, since well i litterally only have juggled with ship design stuff for a couple of hoours so far.
but assuming that 100% pierced armor does nothing there is an argument to be had that armor is all or nothing.

The formula is not damage but damage reduction -- and please see above that I don't really believe it. If you want to use the formula, it means the higher your armor, the less damage reduction. Makes no sense.