The figures I'm using in this post are greater than the actual amounts, but are proportionate to the actual amounts. (The actual amounts are not needed to address my question.)
I completed our (married, filing jointly) 2024 federal taxes the day before the deadline. Based on what TurboTax calculated, I paid $376.00 ($362.00 "Payment Due" + $14.00 "Penalty/Interest"), at the same time with an online transfer from my bank account. The payment was accepted, and my checking account debited.
A few days ago, I got a letter from the IRS stating: "Your 2024 Form 1040-SR was changed to match our record of payment you made." The amount due on that letter is $20.78, which is $6.70 ("Tax you owed" - "Payment you made") + $14.04 "Total Penalties" + $ 0.04 "Total Interest" (totaling $14.08). I spent several hours trying to figure out why I owed more than TurboTax reported I owed, but was unable—and simply paid the requested amount due to the IRS. I'm not interested in contesting the amount; I'm just trying to learn why the numbers turned out the way they did.
From the IRS letter, the total of penalties and interest is, either interestingly—as a clue, or perhaps coincidentally, just a few cents greater than Penalty/Interest from the TurboTax report. Is it possible, that even though TurboTax reports the total amount I owed ($376)—which includes penalties and taxes—that the IRS added penalties and tax to that amount, even though it (already) included penalties and taxes?
Note: The "Taxes you owe" amount on the 1040-SR generated by TurboTax amount was the same as what the IRS letter reported, so that can be removed from the equation. (Of course that amount is calculated by TurboTax, and used to create the 1040-SR.)
2025-05-20 update: I did some more research and found that the total (taxpayer + spouse) of federal tax withheld from our 1099-R forms withheld, as entered in TurboTax ("My Tax Data") is $1,600 greater than is shown on: 1040-SR: Payments, Form(s) 1099, line 25b. Curious why that is.
--
The "Payments you made" from the IRS letter is a small amount greater than the Total payments" amount, line 33. I don't know how to make sense of this, or if it even matters here.
I'm including some additional information. It might lead to more questions than possible answers, but here goes, in case useful.
--
From the "Electronic Filing Instructions for your 2024 Federal Tax Return" section of my TurboTax:
"Your federal tax return (Form 1040-SR) shows a balance due of $376.00"
The Summary on that same page shows "Balance Due With Penalty/Interest" of $376. (That's $362.00 "Payment Due" with $14 "Penalty/Interest" = $376.00.)
The 1040-SR: "… amount you owe." (line 38) also shows $376.00.
--
From our 1040-SR:
The payments I made are from:
Form(s) 1099, line 25b, and
2024 estimated tax payments and amount applied from 2023 return, line 26 (oddly, this amount is $20 greater the sum of my 2024 estimated tax payments) (I'm all but certain there was no amount of taxes applied from my 2023 return.)
