Gotcha on the first couple of sentences, and you are correct comparing our center to the OP's ability to bid. All of our satellite centers have their stuff shuttled to them by one our swing drivers every morning.
As for the last part of your response, I have a feeling that you are right about the miles, wear and tear, and drive time. Because it has been like that for so many years, I think that UPS would win the argument as a past practice. When I say years, I'm talking like 25+ years that a driver has run that route and lived in the city where the satellite is based.