In this example, you are correct that the $1,500 is excluded. However, if customer B had deposited $6,000 to Customer A's personal account, then Customer A would have had more than $10,000 deposited on their behalf and you would have ended up with three Part I's for Customer A.
_________________________
Sola Gratia, Sola Fides, Sola Scriptura, Solus Christus, Soli Deo Gloria!
www.tcaregs.com