It's my understanding that Debt Service Coverage Ratio (DSCR) = Total Debt Service / NOI.

I read that Debt Service Coverage Ratio (DSCR) can be manipulated by changing the amortization period (see text and table below) but I don't understand how that's possible. Or more specifically, how amortization factors into the equation and changes the DSCR value? Even if DSCR is calculated on a monthly basis instead of an annual basis, debt service and NOI are always factored in to the calculation at the same rate so this doesn't make sense to me.

DSCR can be massaged to fit into a lender's "box" by changing the amortization period.In the table below, expanding the amortization period by five (5) years from 20 years to 25 years increases the DSCR from 1.15x to 1.22x. If the lender had a 1.20x DSCR requirement, that one small adjustment can make the difference in getting a loan done or not.