Thank you for your advice. I went back and compared the 1040 from my original return to the new 1040 to be included with the amended return and the only difference is the $18 in income and the new 1040 shows my balance due of $8 more than the original (Original showed $67 due and new 1040 show $75 due). So that part looks good!
The problem is on the 1040-X that TurboTax generated. Both the cover letter and the 1040-X shows I owe $1,598, as opposed to the expected $75). As I mentioned, as soon as I clicked to create an amended return in TurboTax Premier, it change the Fed Tax Due monitor number from $67 to $1598 (but it changed the state tax due to 0, and the message link in Turbo Tax "Why did the refund monitor just change to $0" indicated that it resets the tax to 0, but it did NOT for the federal tax).
Therefore the 1090-X does not reflect the difference between the original and new 1040. Line 6 on the 1040-X shows a net change of $1598 for tax and the "Correct Amount" Column C total on Line 6 does not agree with the newly generated 1040. And Line 18 ("Overpayment, if any, as shown on original return or as previously adjusted by the IRS") on the 1040-X shows $1,523, and I don't know where that came from!!
I think TurboTax has some kind of error in generating the 1040-X.
So what I did that appears to fix the problem: I went into the forms mode, opened form 1040-X, and then I went to the section that says "Original 2023 Return OverPayment Smart Worksheet", and changed the amount from $1,523 to zero. I have no idea what causes that number to be there. But making it 0 causes the 1040-X to agree with the original and new 1040 and the balance due is only $8 more for the $18 increase income, as opposed to $1598 more!
