Yes Jim, I chose to amend the return and emphasize all contributions made in  2020 were qualified for the 100% AGI limit and attached a new Schedule A with the amount on the dotted line. However, processing  has been extremely slow from IRS: taxpayer just 2 weeks ago got a letter stating they looked at the 1040X and nothing further needed from him. I, however, wrote a letter to IRS as if from the taxpayer, and replied to IRS that they still owed the taxpayer for the net investment income tax which somehow they charged him twice for, when they  adjusted for the contributions. So contributions were apparently adjusted to 100% limit, however, they must have manually made the adjustment and in so doing, charged him for the NIIT twice, plus interest. Not material as for amount, but just not right. What a mess! Still I suggest the 1040X route looks best way to me. Hope it works out. Too many clerks and not enough higher ups to put the pieces together.