Whats a mortgage interest adjustment

[ZoltanB45]

I am assuming you are referring to how the mortgage interest deduction is adjusted if the principal is greater than the maximum allowed amount. If you are married filing joint and the the mortgage balance is greater than $750,000,  you are only allowed to deduct a percentage of the interest, depending on how great the balance was.

Page 9 of the link explains a little bit about the limit on home mortgage interest deduction