I think you meant Line 29.

Yep...Thanks Bill.  MC +1

The Medicare premiums that are paid from your Social Security benefits are shown on your Form SSA-1099. The screen where you enter your SSA-1099 has boxes for entering the Medicare premiums. But if you enter them there, TurboTax will automatically include the premiums in the medical expenses on Schedule A. If you want to use the Medicare premiums for the self-employed health insurance deduction on Schedule 1 line 29, do not enter them on the SSA-1099 screen, even though they are on your SSA-1099. Enter them only under business expenses.

Note that the deduction does not go on Schedule C. So, it does not reduce the amount of your net profit subject to Self Employment Tax. It does reduce the amount subject to income tax.

The current version of TurboTax Home & Business for Mac "double dips" the premium paid for Medicare if it's itemized as a Social Security direct payment. To fix this I had to show a negative payment equal to what Social Security paid for my personal medical premiums so that the deduction could be taken only for the business. The underlying code for TurboTax needs to be corrected to guide the user through this without having to perform a kludge.