But it's not really overpaid.  Congress wrote the rules and the IRS followed them (well, mostly).  If the rule was supposed to be "based on only 2021" then there could have been a claw-back (or even a limited claw-back based on AGI like the ACTC mess).

So it sounds like you're just tracking how much you think should have been paid had you been the one to write the tax law.

Rick (with a possibly biased opinion since my $1,400 was based on 2019--but if the rules had been different and I known that ahead of time I would have changed my 2021 Traditional/Roth 401(k) mix accordingly or waited until 2022 to cash out some capital gains.)