If you want elite status benefits on AS, you need to credit your flights to AS, not AA, so you can earn MVP or MVP Gold. If it helps you feel better, AS elites get no love from AA. The only benefit you will sometimes get, especially in SEA, is to board right after MVP Gold when they call for MVP and partner elites. There have also been reports of AA elites being able to get better seats on AS by calling AA for seat assignments, but it doesn't seem consistent and you won't be able to do that online.