I also had this issue. I decided to bite the bullet and do the calculation myself for the one room I rent out, and entered 13% for all my expenses. Then after I had moved on, I clicked 'Federal Review,' and TurboTax found an 'issue' that it wanted me to look at. It wanted me to enter the percentage of the rental use! Now I'm back at the beginning, re-entering all my expenses, and it seems to be running the calculation correctly, calculating 13% of everything I enter as deductible. It even went through my improvements/assets and applied it to everything there too. Now that I'm reviewing that, it reminds me that 'Since I'm only renting out a portion of my property,' I should enter the full asset amount.
Only one remaining issue - I want to deduct the partial cost of all-house repairs, but the full cost of a repair I made for the tenant's space. I entered the full cost repair under 'Miscellaneous.'
