TT does calculate an average within it's system. I don't know exact parameters, but probably beginning principal balance plus ending principal balance divided by 2. IRS publications have ways to calculate, but this simplest approach is probably close AS LONG AS YOU DIDN'T MAKE SIGNIFICANT EARLY REPAYMENT. If just made normal payments probably OK. Other methods to calculate take 12 month end principal balances (Jan - Dec), add up and divide by 12 OR take cash interest paid on each loan and divide by interest rate on that loan to get an average principal amount outstanding, do for second loan and add two amounts together to get total principal amount outstanding. I believe you have to override TT calculation on work sheet if you want to change average principal outstanding to a lower amount to increase deductions. Probably not a huge difference
Based upon your saying 81% of interest was deductible, was your average loan balance around 926,000?
Date is important only if your original purchase date on your property was before December 16, 2017 when there was a $1,000,000 loan balance limitation. So wouldn't affect your calculation as original purchase was in 2018.
Hopefully this helps, if average loan is about 926,000 in 2020 you are probably there.
Post back with questions.
Name probably doesn't matter as I don't believe it shows on any filed form (check). If shows up on actual filing I'd add both to the one line name.
