Thanks - you are probably right on the NA thing, when I fly home from trade shows I always book the later flight then rush to see if I can make the earlier flight. AA allows this free for Platinums.
I assume when I put in my AA number I will be allowed to book seats and board before the general public? My outbound is DFW-FRA-TXL-CPH on an AA J award so I will be on AB the last 2 legs and can check on the VIE-LHR.