Urm it could relate to a specific A/C serial number effectivity and therefore only certain airframe numbers in the fleet had the system deactivated,maybe? AA have a large 757 fleet I understand and the chances of every aircraft being identical with respect to IFE / Airphone mod state are maybe not as remote as some conspiracy theorists would like to believe? Just a thought,and it's open to challenge but look at the fleets of many operators eg Malaysian,VS , seemingly identical a/c with varying IFE / Seat types / Density configs etc.