You can bid for whatever you want (you know the "want" saying...); what gets awarded is up to the company. The AE list is simply the "known openings" that they have--if someone vacates a particular category, then the company can backfill (or not) at their discretion. So, if someone bids out of SEA on this AE, and the company elects to backfill that position, then someone with an appropriate bid in will get SEA....

I've been told that this can happen even without someone bidding out--that the company can elect to award a bid to a category that wasn't "advertised" on the AE. That seems to contradict the language of the AE construct (my read of it, anyway), but it drives home the point of "wanting what you bid...."