I filed Amended returns 2019, 2020 and 2021 in Dec. 2022. That is what I think the IRS can look back on (for errors?) unless they believe fraud involved, in which case than can go back farther. I did not wait for an audit. Chose to be proactive. I might have actually returned more to the IRS than it was entitled. Total for three years was a little over $20k plus the interest. I wrote with the amended return that "I determined that I was not entitled to the AMT credit for the year that this amended return applies to." I received fairly quick responses for the amended 2019 and 2020 returns with interest due notice. No Penalties. I received a response in March 2023 to my 2021 amended return with "no action needed at this time". In Feb. 2024 I received an "we have been attempting to contact you about the interest due" letter. I paid the amount requested and disputed their claim of trying to contact me. Sent along a copy of the letter from March 2023 that said I had to take no action. I received a letter acknowledging the recent payment in March 2024. Hopefully I am all done with AMT.
I do believe TT made the error even though they won't admit it. My non-professional advice would be to calculate what you owe when removing the AMT credit and pay that amount and request the interest amount that you owe.
