“The only thing I can think of is that maybe they meant to send in 1/2 month payment every 2 weeks which means that in a full year you would have made 1 extra months payment. They didn’t spell this out correctly.”
I believe one extra payment will take 5 years off, not 10.The advantage to the bank of having 1/2 the money earlier in the month would have to compensate for the rest. Over the years I have seen a few programs like this but am not sure they were designed to shave years off the mortgage. I think they came with a better rate so the benefit was shared with between the borrower and the leder.