About the Khitan Foundation exp I’m 99.9999% sure, even if I’m wrong it’s because the exp tick we gain every few seconds. About the RSF foundation I’m 100% sure, I even thought it was 15k at first. around 9k exp is from the wall.
That’s even more inconsistency, why gives a door with more hitpoints, but gives weaker armor and weapon, also less exp for T3 building with the exact same materials. The base game did have MUCH lower exp from Black Ice Building but that’s because Black Ice materials are much easier to make.