My 2021 return had quarterly state estimated payments. These totaled to (as an example), $5,605. Turbotax added them (and used in the return) and came up with $6,505.

[JoeHe]

TurboTax 2021 desktop, on an up-to-date Mac.

[JulieS]

We'd love to help you complete your tax return, but need more information. Can you please clarify your question?

Where was the figure used on the return? 

What state are you referring to?

[JoeHe]

The state was California. I entered the four payments as part of the federal data input. When I click "Done" it shows my a total (with the first two digits transposed, as in my example). That was also the figure that was used in determining whether I paid or got a refund. Turbotax, using the incorrect figure, calculated a refund. CA, using the correct total, understandably disagrees. 

[skepticbillpayer]

Possible explanation.

I do estimated payments for CA, as well.  But, usually they only ask for three payments; one of which is in January of the following year.  So, CA will treat the payment in January as a credit toward your total tax due; but the TT will not treat the January payment as a CA State tax deduction.  So the two totals can be different.  I suspect the inverted digits is just a coincidence, in your example the $900 difference might be your January payment amount, for example?

[JoeHe]

Now I see what happened; it's a little different than what you hypothesized.

TurboTax allows for four payments (four quarters, and there's a button to add more). My four quarterly payments were entered in correctly. Somehow, I entered an additional (duplicate) payment. When you look at the list of estimated payments, it only shows the quarterly payments and not the additional payment! (It would have obviously been a duplicate.) It also doesn't show that an additional entry was made.

The total does include the duplicate, and it was happenstance that it looked like a transposition error. 

Obviously, on the data entry sheet, it would be nice to have had some indication that there was more data than was shown on the screen!