I have a Home Equity Line of Credit where only a portion of it is considered home acquisition debt and the remainder is home equity debt. This is treated by the IRS as a mixed-use mortgage. IRS Publication 936 (2022) specifies how the average balance for a mixed-use mortgage is to be calculated using month end balances. I am using Turbotax Premier for Mac for 2022. From what I can tell, Turbotax uses the end of the year balance as the average balance for this type of debt. The average balance is used to calculate acquisition interest which factors into your total mortgage interest deduction. The impact of this issue will depend on how much your month end balances fluctuated during the year. As a work around, I calculated the average of the month end balances for my home acquisition debt off-line. Turbotax allows you to manually override the end of year balance with the correct average balance. In order to do this, you need to go into Forms and select "Home Int Wkst" for the Home Equity Line of Credit where you can override any amounts displayed in blue. In this case, you will need to override the amounts in Section C and F in the Home Mortgage Interest Limitation Smart Worksheet.
