@bbakercpa
Have you tried e-filing after overriding 11(a)? If this works great, but if it results in rejected return, you can undo your 2020 refund as 2021 credit and treat as extra estimated payment for the same amount. Even though TT doesn't do it this way, the actual IRS instructions for Form 2210 indicate that the IRS treats this prior year refund to current year credit as an extra estimated tax payment in the period when prior year return was filed. I tested this extra estimated tax payment tweak and it resulted in a correct value in 11 (a) and since that is what IRS intends to happen, it is a legit alternative to overcome 2021 TT errors in Forms 2210 and 2210AI that TT probably never will fix.
