The second just reflects Congress's attempts to deliberately hobble the USPS in 2006 by requiring them to suddenly pre-fund their pension obligations.
https://www.uspsoig.gov/blog/be-careful-what-you-assume
https://www.bloomberg.com/opinion/articles/2018-04-04/congre...
> The law requires the Postal Service, which receives no taxpayer subsidies, to prefund its retirees' health benefits up to the year 2056. This is a $5 billion per year cost; it is a requirement that no other entity, private or public, has to make.