[Discombulator]

Replying to myself to correct my comment: the pension benefits funding appears to be in general - and differently from what I stated - not much different to the private sector.

The change introduced by the 2006 PAEA impacts however the funding of health care benefits of retirees, which have to be funded at 100%. This is not required of private sector companies.

Additionally, to build up this future retiree health benefits fund, a very front loaded schedule of about $5.7B yearly between 2006 and 2016 was chosen. In fact, the USPS was not able to fulfill this schedule and defaulted on multiple payments.

Best source I have found: https://fas.org/sgp/crs/misc/R40983.pdf