Go to
Personal -> Deductions & Credits -> Mortgage Interest, Refinancing, and Insurance
and enter the first loan. When you get the `Home loan deduction summary' screen you'll see a button labeled `Add a lender'. Click that to enter the second loan. (It works even if the second lender is the same as the first lender.)
If you do that, your worksheets will most likely be correct. But beware: the entry on Line 8a of Schedule A may not be.
