Now I’m really skeptical – I’d want to see some examples before I spent any money on the software
I’ve seen at least four of them. Let me repeat they don’t save you money.
They rely on one simple assumption. That assumption is you have excess disposable income each month above your bills. They apply that entire extra amount to “paying off” the mortgage and carry a big “safety cushion” on an HELOC. Wallah, like magic, the demo pays the loans off years as in a decade plus early.
In the end, the demo is really simple, each month, the borrower is making an extra $1000 or more pre-payment. Period. End of discussion. Take away the extra prepayment and you don’t pay it off early. Make the demo so your bills equal your income and the balance will go up until you trip the loan caps and it straight lines you to an early payoff with a minor little footnote saying ‘larger payments may be required’.
If you have the extra income, just prepay and get an credit card with a fat credit line for emergencies. No extra cost.