n_s_r basically gave you the simple reason why this “program” works, at least in theory …

“Average Budget is disposable income used to “budget” and prepays the loan balance. It isn’t “spent” because they say it’s still available as HELOC.”

If you have a significant difference between your budget and expenses, you can pay it down more efficiently without the HELOC.

The problem is human nature. In any given month if your expenses exceed your budget it is REALLY EASY to cover those expenses with your HELOC thinking it’s a one-time thing. Having this happen a few months out of the year eats away at any progress the program gives you.