Same here. We refinanced it once, and mortgage was sold to a different bank once, so I have 3 1098. Each ~$500K. If I followed the TT instruction on "filling in loan balance on the day you paid it off", I end up having average loan balance of $1.5M. Ridiculous. I opened the forms and looked at the "Deductible Home Mortgage Interest Worksheet" and boy it was wrong on so many levels. Looks like five-years-old coded that thing. For "Months loan outstanding", it simply ignores what you told TT the last day in made payment on the loan. Even though I told TT my last payment was in May 2020, it still says I had the loan for 12 months.... Then for my new loan, even though the "Months loan outstanding" was correctly filled, it does not take that into account when calculating "Average balance". If you only held the loan for 6 months, the average balance should be half the loan amount.
I remember similar problem with this last year. It seems even worse, and more difficult to fix this year. I used to use TaxAct which works great on this topic, switched to TurboTax because of a deal. So not worth it, one of the worst mistakes ever made.
