So, OP here. I did call AA customer service and learned something new:

1. Existing locators can not be combined without releasing and rebooking. This confirms what was mentioned on this post.

2. If miles are bing refunded into the same account, the 150 + 25 will still apply even if they are speerate record locators. you would only pay 150 + 150 if the miles were going back into two seperate AAdvantage accounts.

Regards
David