This morning looks at DEn-PHL and back. Looking at options, no R on the directs- but lots of F seats 737-900- and little in Y---- Middle E- return and a E+ middle there. The Y ticket is expensive, the listed F options on UA.com are pretty close- so I bet I get a pretty good offer after purchase. I get a good offer on DEN-PHL, but no option on the PHL-DEN.

After booking I go to put RPU on it, I have one that didn't clear and not sitting middle on a 4+ hour return is worth it to me. When I bring the upgrade page up, it give me a RPU and a miles option for up to three seats? Apply the RPU and get confirmed.

I just checked tonight and there are a couple of R seats now. Did R inventory open between me buying the ticket and applying the RPU?