Why not just enter the info accurately from the 1098s (I have 2), and when the turbotax "review" triggers the question about entering the amount that the interest is limited to on line 8A, just enter your total mortgage interest amount? I haven't tried e-filing yet, but it got me past the question. My belief is the IRS will only see that amount on Line 8A, nothing about the mortgage being limited in any way.
FYI - I ran through HR Block online to see if they have the same error, and they do.
