what is the exact formula on how much armor the unit gets from armor upgrades?
it looks like units with low armor get the % mentioned in effective HP, aka if spearman has 0 armor, he receives 0,13 armor from +20% upgrade which makes the effective hp roughly 120%. but for heavily armored units, like war wagon, which starts with 0,8 armor, after upgrade it has 0,88 armor, which is like extra 66% effective HP
it looks like units with low armor get the % mentioned in effective HP, aka if spearman has 0 armor, he receives 0,13 armor from +20% upgrade which makes the effective hp roughly 120%. but for heavily armored units, like war wagon, which starts with 0,8 armor, after upgrade it has 0,88 armor, which is like extra 66% effective HP