Tax4fp, I am not having a problem with Line 11, as you are experiencing. The timing of credit of the overpayment from 2020 applied to 2021 was initially an enigma. I had this situation: did not use the annualized income method; did check Part II, Box D (treat income tax withheld on actaual dates withheld instead of the default equal apportionment of annual withholding tax method); paid $300 with 2020 Form 4868 extention timely filed on 15 May 2021; 2020 overpayment of $350 applied to 2021 (i.e., no actual refund payment). TT applied the overpayment of $350 as an estimated payment based on guidance provided by the IRS in 2021 Form 2210 Instuctions, as follows:
First quarter due 15 April 2021 - $50. [I expected that the entire $350 would be treated as a payment on April 15, 2021. But, TT followed what is now my understanding of the IRS position. That is, because the $300 extension payment was made on May 15, 2021, $300 of the $350 overpayment was attributable to a payment made after April 15, 2021, and must be treated as a estmated tax payment made on May 15 in the second quarter. Thus, only $50 of the 2020 overpayment applied to 2021 was treated as an estimated payment paid within the first installment period ended April 15, 2021.]
Second quarter due 15 June 2021 - $300. [As explained above]
To obtain the above result, I went back to the relevant TT step-by-step worksheets and re-entered 2021 tax payments. Voila!
Good luck.
