> they're being required to overfund it

Yeah. I don't have any experience with this stuff beyond planning my own retirement, but I recall playing with the numbers a bit a year or two ago when this was more often in the news. It looked to me like the amount of money they were required to put aside would (if the USPS managed to stay solvent over the decades and continue funding the pension fund) eventually make the USPS pension fund a world financial power.

I admire the idea of forcing a large organization, public or private, to keep its defined benefit plans fully funded. I don't really think that's what congress was shooting for.