@Isaac Brock : it all depends on how often you're at +3 stab. If you want to have free-hands on doing any action you want, you'll probably not often be at +3. And refineries' benefits drastically decrease once you don't have any more techlevel to research (sometime in the 1700's).
Otherwise, a ducat invested through FAA is worth the same as a ducat invested through a refinery. Only the other benefits make a difference. But the investment-bonus is worth the same, or even more for the FAA (which stays fit longer).
And the price of a manu increases with the number of manus you build in all, but moreso with the number of same-type manus you build. When a refinery is worth twice the cost of a FAA, what's the point if base trade income is not double stabcost ? And that every refinery's +1% to TE is progressively less useful (+1% when you're at 70% is twice better than when you're at 140% already), while the FAA's reduction on stabcosts is progressively worth more (-1% when at 100% is worse than -1% when at 60%).*
I advocate a mixed build. I don't say "don't build any refinery", but "build FAAs enough". And "enough" is roughly one for every ten provinces, more or less depending on your DP sliders & BB (and aims).
* I use % for percentage point here, not percent. Don't be confused.
Otherwise, a ducat invested through FAA is worth the same as a ducat invested through a refinery. Only the other benefits make a difference. But the investment-bonus is worth the same, or even more for the FAA (which stays fit longer).
And the price of a manu increases with the number of manus you build in all, but moreso with the number of same-type manus you build. When a refinery is worth twice the cost of a FAA, what's the point if base trade income is not double stabcost ? And that every refinery's +1% to TE is progressively less useful (+1% when you're at 70% is twice better than when you're at 140% already), while the FAA's reduction on stabcosts is progressively worth more (-1% when at 100% is worse than -1% when at 60%).*
I advocate a mixed build. I don't say "don't build any refinery", but "build FAAs enough". And "enough" is roughly one for every ten provinces, more or less depending on your DP sliders & BB (and aims).
* I use % for percentage point here, not percent. Don't be confused.