Apparently you didn't read the item Weco referenced or you would have found that this crap about 'healthcare' costs is just that, CRAP, forced onto the Post Office by Bush and his Republican enablers who's only goal was to destroy the largest union left in the country.
Excerpt below was taken from Weco's item:
The Postal Service is NOT broke. Indeed, in those four years of loudly deplored "losses," the Service actually produced a $700 million operational profit (despite the worst economy since the Great Depression).
What's going on here? Right-wing sabotage of USPS financing, that's what. In 2006, the Bush White House and Congress whacked the post office with the Postal Accountability and Enhancement Act--an incredible piece of ugliness requiring the agency to PRE-PAY the health care benefits not only of current employees, but also of all employees who'll retire during the next 75 years. Yes, that includes employees who're not yet born! No other agency and no corporation has to do this. Worse, this ridiculous law demands that USPS fully fund this seven-decade burden by 2016. Imagine the shrieks of outrage if Congress tried to slap FedEx or other private firms with such an onerous requirement. This politically motivated mandate is costing the Postal Service $5.5 billion a year--money taken right out of postage revenue that could be going to services. That's the real source of the "financial crisis" squeez-ing America's post offices.
But it's not the only hocus pocus that has falsely fabricated the public perception that our mail agency is "broke." Due to a 40-year-old accounting error, the federal Office of Personnel Management has overcharged the post office by as much as $80 billion for payments into the Civil Service Retirement System. This means that, far from being a drain on the public treasury, USPS has had billions of its sales dollars erroneously diverted into the treasury. Restore the agency's access to its own postage money, and the impending "collapse" goes away.
But then it's very likely that you haven't read the item YOU referenced since it basically says the same thing, the Post Office is being burdened with a total unprecedented requirement to pre-fund in 10 years the healthcare costs for the next 75 years worth of employees, most of whom have not even then born yet. Perhaps we should tell the Pentagon that they must do the same thing. Maybe they'd be forced to give up a few aircraft carriers or the next billion dollar a piece fighter plane in order to cover the healthcare cost of every solider, sailer or marine that will serve over the next 75 years, and this must be done in 10 annual payments starting tomorrow!

OCU