I think the PBs go the booster pump, Polaris 380 route for convenience. It offers them both more profit by selling you 2 items instead of one and less headaches. They don't end up with a used Polaris 360 when the existing pump can't drive one. That said I think the local pool store I buy my DE from could of sent me home with the pressure test kit to see if I could operate one instead of telling me I'd definitely need a booster pump. For the pool owner the ability to put the booster pump on a timer can be a big win in the laziness department. If I only had a dedicated return line and an electrically operated valve I'd be in heaven. ;-)