Added 8 minutes later
It costs the same everywhere.
And what is the "+"?
I would like to see more "negatives" of 5 compared to 3 in HoMM 6.
Yes, but in Heroes 3, the fortress is already built at the beginning of the game, while in Heroes 5, you have to spend resources on this damn fortress first in order to build a stronghold, which should be built at the beginning or cost less.
I don't understand, what negatives of 5 compared to 3 would you like to see?