Here's some of my data points (note that for some connecting flights it was actually outside the window):

DNR = did not receive. N/A means E135/45 flight. Haven't flown in over a month but have a fair amount of activity coming up in the next two months. Would be curious if people wanted to talk about actual data points (I just used my "YOU'VE BEEN UPGRADED" emails to generate this data).

Upgraded times are in mountain. flight times are local, but were converted for finding the time delta of upgrade and pushback.