How are division's armor and piercing calculated?

[podcat]

its a weighted average. (40% for piercing, 30% for armor)

 

[podcat]

Interesting. But why is weighted like that and not strictly averaged?

it promotes a combined arms effect. Otherwise adding a few AT guns would basically do nothing or players would want to only do only-armor divisions etc.
The idea is that armor/piercing are the quality of your best stuff having an effect (so there is a poitn to mixing in some tigers with mediums and still feel their armor bump) while hard attack and softness is your averageness

i think the reason why support is calculated is, that it also has disadvantages to include them. So that it doesen´t become a nobrainer to add them.

yeah basically