Program wants you to track if at any time you have mortgage loans in excess of $1,000,000 or home equity loans in excess of $100,000 so that you do not deduct interest on the portion of the loans in excess of these figures.  The links tell you if your loan is in excess of this that you will need to do a manual calculation to adjust the amount of interest you can deduct.

IRS Publication 936 - Mortgage Interest (see page 3)

https://www.irs.gov/pub/irs-pdf/p936.pdf