I have same problem on primary residence for 2 1098 forms one before and one after refinance. I followed exact instructions to enter the 1098s plus a third one for the points paid alone and with each additional form I add, in any order, the deduction goes down! I tried a single 1098 with the refinance date of origination of loan (which only gives me 68% of deduction for the interest (limited to $750k) and finally I end up with close to the correct deduction ($10 less than my own calculation). It's infuriating! I cannot submit my return this way because it is incorrect to put two separate 1098s that I received on one, even though both at same lender.
If you have received more than one 1098 form, I will recommend you to combine all 1098 forms and enter as one. I am attaching a TurboTax link for the instructions how to do claim your mortgage interests. Click here:
For tax years prior to 2018, your mortgage interest deduction is generally limited if all mortgages used to buy, construct, or improve your first home (and second home if applicable) total more than $1 million ($500,000 if you use married filing separately status). Beginning in 2018, this limit is lowered to $750,000. For more information about the mortgage interest deductions, click here: Mortgage Interest deduction
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