I know that the desktop version allows full access to the worksheets used for the mortgage calculations. You can even modify some of the entries in the worksheets but that often causes other errors and Turbo Tax may not e-file your return if you do. I don't think you can review the worksheets in the online version.
As far as entering the 1098s, do so in the order of origination: A then B then C. Box 3 of the 1098s for loans B and C should have the origination date for loan B.
Loan B:
This loan was paid off or refinanced in 2024 for loan B: YES (box is checked)
Is this 1098 the most recent? NO
Is this loan a refinance of a previous loan? NO
Loan C:
This loan was paid off or refinanced in 2024 for loan B: NO (box is unchecked)
Is this 1098 the most recent? YES
Is this loan a refinance of a previous loan? YES
Did you use your loan for anything besides paying off the existing loan? NO
After entering all three 1098s and clicking 'Done', you should get a notice that your mortgage deduction is being limited and the option to enter your own amount of deductible interest. Based on how turbo tax calculated the deduction last year, I am sure you will want to enter your own value. Turbo Tax would calculate the average balance for each mortgage using the opening and ending balances for the year. To determine the limit, it would add the average balance for loans A and C only (loan B is not included because it was refinanced).
Note: I didn't include the $400K down payment on loan C that you said you were planning in my previous calculations. I used $796K for Oct for Loan C. If you made the $400K down payment, you should be able to deduct all of your interest using the Statement Balance method and even Turbo Tax would probably come up with around 96%. If you didn't make the $400K down payment, the difference between the Statement Balance method and the Turbo Tax method will be significant.
