UPGRADING USING BA MILES/Earning on AA
 

I have already booked a ticket in WT+ on BA and I inserted my AA advantage account to credit the miles to my account with AA for that trip.

Is it possible that I still use my miles in BA account to upgrade to CW and still post the miles for that trip to my AAadvantage account or I still have to post the miles for that trip to my BAEC account only ?

The usual procedure is to use your BAEC number when you make the booking, and change this to your AA number after upgrading. I have done this, but although the AA number was on my BP, the miles got credited to BA. Filling in the claim form on aa.com soon retrieved the miles.

I have no idea whether BA can process an upgrade with the AA number in your booking, but it should be easy enough to change it to BA first, and swap it back later.

Do you mean here that you got the miles for the same trip on both programs or you ended up getting the miles just on AA not on BAEC ?

I expected to just get the miles on AA, but at the moment I still have them on BA too.