Every cost cutting strategy that top management tries to implement is sabotaged by operations and labor there. Plant employees have been paid overtime long enough that they think they're OWED that overtime. When it's threatened, they slow down, mass sick calls, clog machinery, everything but strike as they are forbidden. The federal procurement process we're forced to utilize makes it almost impossible to effectively purchase equipment without up front payment, with no guarantee it works as promised. The PRC constantly works against the USPS even though they're supposed to help it operate.
Two years ago the Post Office used 180,000,000 gallons of gas. You can see what a $1 increase can do to costs. (note: Competitors have just added an 8% fuel surcharge on their shipping rates)
There's also a belief by Congress that postal carriers are vastly overpaid for the job they do relative to the private sector. They can't cut pay due to contracts, but they can shift standards -- RRECS was a prime example where they now get far more productivity from rural carriers than they did before the system. Look for the next huge move to be against city carriers, especially targeting their overtime. They could start with freezing expansion of regular routes and reducing the number with a freeze of some sort. Then hire CCA's to get routes carried with labor costs roughly half of what a regular makes.
Congress SHOULD act to make the USPS a fully integrated part of the Federal government. But they wont. We are truly between a rock and hard place.