can the amount of medicare premiums deducted from my monthly benefits be taken as an over-the line adjustment on 2020 form,line 10. I am >2% shareholder/employee of an SCorp.

Yes, you can use medicare premiums paid from your social security benefits as self-employed health insurance premiums.  Medicare premiums you voluntarily pay to obtain insurance in your name that is similar to qualifying private health insurance can be used to figure the deduction.

Medicare premiums you voluntarily pay to obtain insurance in your name that is similar to qualifying private health insurance can be used to figure the deduction.

For additional information, please refer to the following link:

Can medicare premiums be used as self-employed health 

Your self-employed health insurance deduction cannot exceed the amount of the reimbursement from the S corp for healthcare, reported as wages box 1 of your W-2 from the S corp.  The deduction goes on Schedule 1 line 16, which TurboTax will do automatically when you enter the Schedule K-1 (Form 1120S) from the S corp and indicate that you personally paid for healthcare and the S corp paid you wages.

Thank you for your response. I do have an additional question to ask ....is a > 2% shareholder/employee of an Scorp considered self-employed? This question came up when I read the link you referenced to me. I appreciate your time and consideration.

You are considered to be self-employed only for the purpose of the self-employed health insurance deduction, not for any other purpose.

I've also add a bit to my previous reply.