Overlapping Mortgages - Purchase and Sale Same year

Trying to calculate how to handle the overlapping mortgage interest on two properties. Property 1 was a condo originally purchased in pre-2017, but refinanced in 2020, and sold in October last year. Property 2 was a house Purchased April last year, and has a regular jumbo and a heloc loan. Property 1 was my primary residence till June when I moved into property 2. I've done a bunch of the calculations, but unsure how to get this right. Average monthly for property 2 is much higher than 1. Do I do the averages for only the months that the loans existed (ie Jan-Oct for Property 1, and April-Dec for Property 2) or make it an average for the year end on each loan, then just add up the total of mortgages for each month? Do I use the lower or higher average for overlapping months? Kinda grasping at straws between the instructions and the IRS docs which aren't clear.

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