On another forum (possibly UA), people were recommending that if you flew paid F and were concerned about downgrades/change of gauge/etc., you should also do a dummy booking in E at the same time, and do a screenshot of the price for E, purchased in advance. That way, you could use the screen shot to argue the fare differential should be "X" not whatever low-ball number the airline is offering.

Whether this technique actually worked -- or will work for AS -- is another matter!