That username is already taken, and I know who he is.

Phone agents seem to say different things, even with great degrees of confidence. DL doesn't publish information about the GUC/RUC versus miles upgrade priority ranking. Indeed, I've been told that the order of processing upgrades using instruments depends only on the time of request and not fare class or elite status, but I don't necessarily believe that either.

OTOH it is true, and is published DL policy (with many reports of it being followed) of miles upgrades not going to the gate, although some GAs are willing to process mileage upgrades at the gate if they have time and know how to do it.

It's also true that upgrades supported by GUCs/RUCs are ranked higher (assuming that the request has been done correctly by DL agents, which is a big qualification) than free elite upgrades at the gate and before then, they pull from different inventory classes.