I had a flight on Monday with a "Y" fare and didn't get upgraded at the window, but got the upsell at check in for $99. I didn't take it and ended up getting the only upgrade on the flight (there were 4 seats available at check in, don't know how many of those seats went to FCM vs. late purchases or SDC). It kind of rubbed me the wrong way to see them selling check in upgrades when I had a Y ticket and hadn't gotten the bump, since my Y ticket was already more expensive than discounted F.