Postal

Does anybody know how the post office decides how many people should work at the window of a particular post office branch? It seems to me that there are far more people working the windows at the post office branches in the wealthier neighborhoods in Manhattan than in Queens, and more in Queens than in some poor neighborhoods in Brooklyn. But what I don’t see is any correlation between the number of people working at the windows and the number of customers using the post office. There is always a line to the back and a wait of at least 40 minutes at my local post office, but things move much quicker at the ones in Manhattan (where there are usually more people on duty at the windows).