OK, so a word of warning...
Following my lucky INVOL SKED CHG, a quick check of my OTP-PHX booking showed that it was still "On Request" 5 weeks after I made the booking !
I just spent 30 minutes on the phone with AA sorting this out - it seems that many people who paid using PayPal in a currency other than their own (me included) have been snarled up by a PayPal system issue which has resulted in many reservations (including mine) sitting in "On Request" indefinitely.
Luckily the very good AA agent managed to get the booking unfrozen and payment taken off a new credit card.
So
check your AA bookings !!! If it says anything but "Ticketed" then you should probably give them a call...