It seems like only the first eight buildings you build/upgrade have their buff applied. Any upgrades or new buildings after that point do not add to the buff. I should have +12 melee damage from upgrading one building to it's max level but I'm only getting +3 because the initial building was in the first eight. It appears that the buff is generating a list of increases and only using the first ones (Ie. +25 health, +25 health) instead of adding them all together and displaying them like +50 health. Every video I've seen of the buff displays the same problem.