EPR and investment return adjusted debt paydown accounts

Does anyone have any experience with investment return adjusted debt paydown accounts?

A CFP I met with this morning went deep down the EPR rabbit hole, and he’s wanting to meet again to discuss investment return adjusted debt paydown accounts.

Are these a product on the investment side? An arbitrage strategy for private wealth management clients? Or a strategy that involves coordinating 2 products and a mortgage advisor, financial advisor, and client?