I have never figured out AA.com seating. I have a window as my preferred seat type in my profile. I actually sit in aisles in coach but windows in first and business. The preference is there so AA.com will sign me a window if my upgrade clears. The weird thing is that it only assigns a window half the time even when windows are open. However in coach (when I make an online res) it will always assign a window and if there are no windows available and tons of aisles and middles it will assign no seat. So I know the system works for coach just not business and first.