Anybody wondering why their upgrades are clearing later (or not at all)? Here's one data point that might help explain it.

I just booked LAX-MKE for later this week and found that on some aa.com-suggested itineraries, the instant upgrade P was the cheapest available fare at $440 each way plus taxes. Cheaper than the one-way M fare at $480++ or the one-way H fare at $580++ and of course cheaper than the one-way full Y fare at $742++.

I've often seen the instant upgrade fare cheaper than full Y but rarely have I seen it the cheapest available seat on the plane. In the past, I've also been upgraded upon booking last-minute deep discount coach fares when booking within the upgrade window, but those deep discount fares are typically much less than the P fare.

This forum has seen many complaints over the years that AA's upgrade policy leaves last-minute flyers (typically on expensive fares) unable to secure an upgrade because so many advance purchasing EXPs and Platinums have already soaked up the inventory of big seats. Well, perhaps this is AA's way of making certain that some last-minute booking EXPs (like me) get F seats well inside the 100 hour (and even inside the Plat 72 hour) upgrade windows.

As an aside, anyone from LAX needing to be in Chicago (or north suburbs) on short notice should look at MKE fares, as the $440++ one-way instant upgrade fare is a pretty good deal. If you want to end your trip at ORD, simply book as one-way and nothing remains to be canceled when you throw away the ORD-MKE segment. Looks to me like the $440++ P fare continues well into summer.