Thank you all for your feedback. So it looks like in 2020 I had Turbo Tax apply my state tax overpayment toward 2021 estimated taxes. Looking at the 2021 Colo Estimated Tax worksheet that Turbo Tax generated, it reduced the amount of one of the payments by the amount of the 2020 amount. I paid the adjusted amount - full estimated amount minus the 2020 overpayment applied.
So I'm wondering if I have a leg to stand on to file a protest? If not, should I have not applied the overpayment? It seemed like a good idea at the time.
