I found it. Here are details in case this helps others.
Summary: When you take the standard deduction, mortgage interest and real estate taxes should go on lines 16 and 17 of 8829 instead of 10 and 11. In order for this to happen, you need to take specific steps in the interview, namely:
- Business
- Business Income and Expenses
- Edit your business
- Business Expenses > Home Office Expense
- Edit your home office and answer the next ~12 questions.
- Then, I choose “I’ll enter actual expenses spreadsheet-style”.
- Then, the key screen appears, entitled “Let’s confirm mortgage interest applies to this home office”. It has a checkbox next to “Yes, include for this home office deduction”. It also has a line that says, “If you’re not itemizing deductions, uncheck the ”Yes, include for this home office deduction” box below.” Uncheck the box. Press “Done”.
- A few screens later comes one entitled, “Enter expenses for entire home”. On that screen, it says, “If you are not itemizing deductions, enter your mortgage interest as Excess Mortgage Interest, and your real estate taxes as Excess Real Estate Taxes.” Populate those two fields.
