1040, estimated tax input screen, has 2 column headings Federal and State, under the Federal heading there are two columns, amount, and a drop down to choose US or a state.  This choice column under Federal makes no sense to me.  Payments for Federal would always be to the US Treasury so you would never choose a state in that but always US.  Therefore, if no need for any choice exists, why is this choice column here?  Perhaps there is some purpose for it I am not aware of?  If so, that should be in the FAQ on this screen and if not that column should be removed as it appears to just be extra data never used.

Further, when you rolled my client 1040 previous year 2020 Federal overpayment into 2021, you correctly listed the amount in the Federal column, but you set the state selector to IL as that is his domicile.  That then was a waste of my time I had to go look at the actual 2020, see the overpayment applied was actually for Federal not IL, and then change that selection from IL to US.   Thus you wasted my time checking on that and introduced a query in my mind for this comment as to why ever one would use such a column to cause anything different to hit a Federal or State return for a Federal payment and I am not aware that ever is needed.   Either way, by putting IL there you wasted my time chasing this so please either 1) remove that or 2) put in an FAQ on that screen why you have it there for even one single known reason where it makes any difference in any kind of return.    It looks to me like a programming flaw and not a valid tax reason.    I say a flaw as it introduces on the same screen what would appear to be two ways to enter a state payment, either in state column, or in federal column and choose a state; that is terrible thinking, pick a tack and stick with it.  We do not have time to wonder what it is you are going to do with the amounts we enter on this screen for such a selection