When I enter mortgage interest for real estate that was converted from personal use to rental use on the 'Home Interest Worksheet', and I also indicate the days personal vs rental use on Schedule E (in my case, it is 155 personal, 210 rental), Schedule E correctly shows the breakdown of interest between rental and personal. However, Schedule A adds the Total Interest reported PLUS the personal use interest.
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Late entry: I couldn't find a way to delete this post. I addressed this by NOT entering the interest in the Home Interest Worksheet', and only entered it on Schedule E. To me, this wasn't clear in that the worksheet 'Note' did not clarify treatment of property that was converted mid-year.