California 540NR Schedule X instructions to recoup incorrectly withheld taxes

[taxius]

I'm trying to file an amended tax return with CA to get back incorrectly withheld taxes after I moved out of the state. 

It's completely unclear to me how to fill out the California Schedule X ("California Explanation of
Amended Return Changes") form, the FTB instructions online do not help and when I called the FTB customer service they told me they do not provide any assistance with filing and referred me to third party tax preparers. Other than needing clarification on this, my taxes are extremely straightforward: one employer, single, standard deduction, no special circumstances, other income, events, etc. 

The basic situation is that I was a resident of CA, then I moved out of CA permanently in August of 2020. My employer incorrectly withheld taxes for the rest of the year. 

I have finally received a corrected W2 (W2C) which fixed the reporting of my income, however it doesn't seem like turbotax is handling the Schedule X form properly. The language is ambiguous, and I can't any resources online that help despite extensive searches.

So my question is, if I am attempting to get back incorrectly withheld taxes for part of the year, how should I fill out the Schedule X? 

Line 1 is "Enter the amount you owe, as shown on the amended tax return", which is $0 according to the 540-NR amended return on line 121 ("AMOUNT YOU OWE"), after entering the W2C data. 

Line 2 is "Overpaid tax, if any, as shown on original tax return or as previously adjusted
by the FTB.". This seems straightforward, I have an overpaid tax amount in my original return and that was refunded to me in my original return.

Line 5 is where things get confusing. "Tax paid with original tax return plus additional tax paid after it was filed.". I did not pay anything when I filed my original return. Do I enter $0? Do I enter my entire withholdings for the year? Do I enter the difference between my original withholdings and the corrected state tax withholdings?

The rest of the lines seem to be derived from adding and combining these lines. 

Some made up numbers for example:

Overpaid tax on original return: $1,500 (which was received as a refund in 2020)
Total CA withholdings in 2020 on original return: $20,000
Total CA withholdings after entering W2C on amended return: $11,000
New refund amount on amended return: $800

In this scenario my expectation is that since I had $20,000 withheld to CA in 2020, but was supposed to withhold only $11,000, I should get back about $9,000 minus the original refund of $1,500, so about $7,500 refunded. 

I just don't see how to fill out the Schedule X to indicate this example. 

[MonikaK1]

It depends. Did your employer withhold and remit $20,000 in California taxes to the state?  Or did they withhold and remit only $11,000? Did the corrected W-2 change the withholding or the income attributed to California, or both? 

The refund you receive based on an amended return would normally be the difference between the bottom-line overpayment on the return as originally filed (Line 97  / 99 of the 2020 Form 540) and the new total overpayment on the same line of the amended return Form 540. Based on your example, the total overpayment decreased by $700.

See here for the instructions to Schedule X for tax year 2020.

See here for Schedule X for tax year 2020.

See here for Form 540 for 2020.

Line 5 – Tax Paid with Original Tax Return

Enter the amount actually paid with your original tax return. Also, include any additional payments of tax made after the original tax return was filed. Do not include payments of interest or penalties.

The refund subtotal (the amount you expect to receive as a result of amending the return) on line 9 of Schedule X would be the amount on line 6 minus the amount on line 3.

[taxius]

Thank you @MonikaK1 

The employer withheld and remitted all $20,000 to the state.

The W2C corrected the income attributed to CA, it did not change the amount that was withheld. For the sake of the example we can say it changed income attributed to CA from $200,000 to $110,000, while keeping total federal income at $200,000.

The bottom line is that (in the example) I paid ~$20,000 via withholdings when I only owed ~$11,000. 

I've seen the instructions for the schedule X, the instructions are ambiguous to me as a layperson. "Enter the amount actually paid with your original tax return."

What would I enter on line 5 given the details above?

[MonikaK1]

Based on the premise that you overpaid your California tax on the original return because too much of your income was attributed to California, and that is what you corrected on the amended return:

The amount on line 1 is the tax paid per the amended return, which appears on line 65 of that return.

Line 2 is the refund shown on the original return, line 97/99

Line 3 is the sum of 1 and 2, or the revised tax plus the amount of the refund you got originally.

Line 4 is the refund shown on the amended return, line 97/99

The amount on line 5 is the tax paid per the original return, which appears on Line 65 of that return.

Line 6 will be the sum of line 4 and line 5.

Line 9 is the amount on line 6 minus the amount on line 3, and represents the refund you will get back from filing the amended return.

See also this tax tips article regarding amending a state return in TurboTax.