Originally Posted by IceFlash

There could be a scenario where the senior pilot could have lost something. Let's say a hypothetical AE has 1 vacancy. The person that wants to leave the base bids out, leaving 2 open spots. The top 2 senior pilots would then be awarded those positions. On the other hand, had the pilot that left been able to swap with another pilot previously, his position would not have been available to backfill. So only the 1 most senior pilot would have gotten the awards in the same hypothetical AE.