Hello
othermaster and welcome to FlyerTalk.
You would need to pay AA for for an airport upgrade not BA and if you did, you would not receive any additional tier points at all. AA's policy is different to BA's for airport upgrades.
I've suggested to the mods that they merge or delete the other version of the same thread you started in
Miles&Points >Information Desk as it's best to post questions in only one part of the site.