If a supposedly user-fee-funded agency is losing money, then each transaction is at a cost to the taxpayers, stupid DU tools, even in the unlikely event all those letters were written when the postal employees were off the clock (And what are the chances of that?).
Also, 37 pounds of mail? BFD. It doesn't hurt the recipient, he can just leave it all in the box unopened, after sorting it to get anything that looks like a bill or mail he actually wanted out of it.