This is what I'm trying to understand. Suppose I haven't been EUAed at T-24. In terms of my upgrade, there's no advantage to me of checking in early, but is there a possible advantage of delaying my OLCI in the hope that an upgrade seat will open up and I can grab it? In other words, from the perspective of maximizing my upgrade chances, should I delay OLCI and, if so, should I continue to check delta.dumb as often as possible until I must travel to the airport? Should I even not do OLCI (assuming that I haven't yet gotten the upgrade) at all and wait to check in at the airport?

With NW, I was always told never to do OLCI if you still want an upgrade, as once checked in, the only possibly way you can get an upgrade is at the gate, even if upgrade seats open up before that. My understanding was that the NW EUA algorithm continued to run periodically after T-24, but against the list of those who were not checked in. However, I never believed that continuing to check the computer could up my odds in this situation, only let me know if the upgrade had recently cleared. I'm convinced that it played out exactly this way for me at least once.