Based on the fact that the 9th is overturned more than it's upheld, I'd say their ruling is a clear indication of the USPS's being in the right.
The reason is the higher level manager just wants the dispute to "go away" and may well wrongly harm the postmaster.
Sometimes the postmaster gets lucky and manages to find an "expert" in Headquarters or an appropriate HFU to intervene ~ other times the postmaster has to go outside to a lawyer.