I noticed now several times, that my Prestige increased by 2 instead of 1 after I selected an Almshouse when one of Towns reached Level 4. The last couple of times I made sure nothing else would happen during that turn, that would increase Prestige, to make sure it really was the Almshouse selection. At one point two of my Towns reached Level 4 at the same time and I selected the Almshouse for both. Afterwards, my Prestige was 4 points higher than the turn before.