@marcuscato wrote:
Even though details are same, in this question I am asking if I can use tax amendment for SSN and Medicare part. Given the many layers to this puzzle, I decided to open a separate question
Please don't do that, ask your question as a comment in the previous thread. Otherwise, the person answering here may not know the details that were previously discussed and give a duplicate or incorrect answer. If you keep everything together, then everyone (experts and you) can see everything in one place.)
The answer, however, is you will not file an amended tax return. If the company only changes your social security and medicare tax, that does not affect your income tax.
As I answered before, the company can only legally change your social security and medicare withholding (W-2 boxes 3-6). They can't change your box 1 or box 16 taxable wages because those monies were actually paid to you in 2020 and the W-2 must reflect what was actually paid.
If they change boxes 3-6, and refund the excess social security and medicare withholding, that saves you having to file a claim for the social security and medicare tax on form 853. You will still need to file a claim of right on your 2021 income tax return to recover the income taxes.
If the company changes your box 1 and box 16 taxable wages, that would be a violation of the law by the company. You might use that information to file an amended 2020 return instead of using a claim of right on your 2021 return, but that would be improper. (It might be the path of least resistance, but before you did that I would send you to a tax professional for advice. And I don't think the company will do that unless they are a small company managing their own payroll and are confused about the law. I think the company will only adjust boxes 3-6.)
