In my case I had 2 mortgages with different banks on two properties for part of the year. One of the mortgages was before 2017 and one was new in 2020 plus I refinanced the 2020 mortgage. Not sure if Galen had multiple mortgages in between buying and selling a home. Anyway, based on my understanding of the rules for applying the limits, if one has multiple mortgages at the same time, one needs to aggregate their different mortgages to determine where they are with regard to the limits. Even if the individual mortgages are below the limits, in the aggregate they may not be. Plus, in my case I had different limits to deal with. So, as one can see, this can get pretty complicated (which may be one reason why TT doesn't have a fix for this yet). I ended up creating a spreadsheet that tracked all of this in the aggregate by month, applied the respective limits, and then pro-rated the interest similar to how it was described by Galen. For me it would have been difficult to determine how to change Form 1098 inputs on TT in order to come up with the right interest deduction.
