Originally Posted by
Hartmann
this includes mileage upgraders, non-rev, etc.
More to the point, it includes Y-ups as well. Chances of the non Y-up upgrade on the transcons are historically 1/flight on average. I'm guessing that a U fare won't get that one. I did have a transcon with empty seats in F on a Saturday mid-afternoon eastbound, but I assume those are rare.