If you have your Medicare premiums paid from your Social Security benefits, the amount paid for the Medicare premiums will be shown on your Social Security benefits statement Form SSA-1099. Shown in Description of amount in box 3.
Mine always has.....well, that is only if you are having Medicare premiums deducted from your regular monthly SS payments .
There is a description box on the SSA-1099 that shows the total Part B and Part D premiums for the year, and it does include whatever extra paid for those in IRMAA situations...thus the proper total for each.
TTX does let you enter those amounts when you enter your SSA-1099 into the software, then transfers those amounts into the Medical deductions section....in case they are needed/used there.
If you are self-employed, there is also the possibility of claiming the Medicare payments as a self-employed health-insurance deduction instead of as a Schedule A medical deduction. The amount that is claimed as a self-employed health insurance deduction cannot also be claimed on Schedule A line 1. You do that in TurboTax by omitting the Medicare premiums (or at least the portion of those claimed as a self-employed health insurance deduction) from the Medicare boxes when entering the SSA-1099.