Man, Cexshun, you do like to keep me busy . . . lol . . .
I can shed a little light on the priority mail procedure, which while it won't change anything for you, will help explain some things . . . .
. . . USPS does not have it's own airfleet anymore . . . most of our air-transport Priority mail goes on FedEx planes . . . we lease a set percentage of space on their cargo planes . . . . overflow needs to wait for additional flights, or find room on commercial planes. . . .
. . . When a Priority package is mailed at a small PO, it is sent via truck to a dedicated Priority Mail Processing Center each night . . . . there, the parcels are sorted by major airports, and then trucks pick them up, and bring to the local airport to be loaded onto FedEx planes . . . . now, the amount of time this takes all depends on many variables, such as the local PO's proximity to the Priority Mail center, the Priority Mail Center's proximity to the local airport, the size of the local airport, the number of FedEx jets flying out of the local airport, the volume of Priority Mail that is sent out each night vs. the allowable volume on the FedEx planes, the FedEx flight patterns, airport proximity to PMPC on receiving end, and PMPC proximity to local PO on receiving end . . . . some area's of the country may see an extra day, because an incoming flight made it an hour late, causing a chain reaction which makes the dispatch miss the trip to the local po by it's cutoff time in the morning . . . .
Also, West to East should theoretically take longer, because there is smaller tolerance for delays based on time zone difference, but some of these variables can combine to make the east to west less predictable. . . usually, if you're seeing delays from one origin point, it is a result of airline logistics and not the local office . . .
Due to security concerns, dispatch and flight information should never be made public, and the best thing to do is to test it yourself to verify delivery standards . . . mail a few packages to the same zipcode to get a good feel for the normal delivery time . . . . 3 days coast to coast for $3.85 is still a very good deal, IMHO . . . .