It's all about how much of each payment goes to the privilege versus the interest. Generally speaking the first 5 years of your mortgage payments go all to the interest and not to the principle even on a 15 year mortgage. The loans are not a normal straight amortization table at least in my years of mortgage brokering they never have been. So if you are on a 15 yr mortgage but and you pay the normal payment it will take u 15 yrs. However if you are on a 30 year and you pay that same mount as the 15 yr payment you will have money going towards paying down the principle right away. On a normal mortgage loan table that means you will save about 3.5 years on average of payments. Turning the same loan from 15 years into 11.5 ish years. Do the math, look at an amortization table the facts are there.
I used to work in home mortgages right out of school. Trust me it's a trick of the trade. As a home owner you should never take a 15 year mortgage. If you do you got ripped off.
Also in many cases the 15 years mortgage will have a higher interest rate not a lower one. Because it puts your debt to income ratio at a higher level making it a riskier loan for the bank.
That's what I mean about this article it is completely false and intentionally misleading. +Michael Mason