This might be different elsewhere, but here, the apartments on lower floors are typically rented and they're cheaper than those on higher floors. It's the case at the building I currently live in, although it's because on the lower floors, there are more apartments (smaller ones) than on the higher ones. Roof apartments are all sold out, not rented.

So, I could imagine, that the higher floors are occupied by more wealthy people, who might be less prone to alcoholism. This theory, however, doesn't check out for high rise prefab houses. But it could perhaps cause the deviation?