u/Wilson8151

Hey all! I'm hoping someone here can help me with a question about multiple W-2c forms. I'm planning to get an outside consultation, but want to be as prepared as possible going into that meeting. I appreciate any help anyone can lend. Thank you!

TLDR

I'm a salaried W-2 employee for a company that uses an outside payroll firm.

In January, I received an incorrect W-2 and was issued a W-2c in March. However, that W-2c was also incorrect. I filed a tax extension, and this summer I received a second W-2c. On the first W-2c, the payroll company fixed the original problem… but created a new unnecessary one in the process. On the second W-2c, they updated a completely different box.

Now I'm wondering: are W-2c corrections cumulative (i.e., do I enter the changes from W-2c #1 and W-2c #2), or does the second one supersede the first (i.e., ignore the changes on W-2c #1 and only enter the changes from W-2c #2)?

Either way, it creates a problem for me. Superseding (ignoring #1, using only #2) doesn't fix the original issue that made the W-2c necessary in the first place. Cumulative (using both #1 and #2) fixes the original issue, but locks in the mistakes from W-2c #1.

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Now for the much more detailed version, for those who are interested:

On my original W-2, all the numbers were correct except Box 12a, Code W: $12,498.96. This box should have read $8,000.16.

The error was in how our HSA premiums and HSA contributions (the latter a combination of my contributions and the company's) were viewed.

W-2c #1 made this correction… but then took the difference between the two figures ($4,498.80) and added it to my income. They also issued changes to Boxes 1, 5, 6, 16, and 17. Interestingly, they did not change Box 3.

I raised this as an issue, and months later they issued W-2c #2. The change on this one was:

Box 12a, Code DD: $13,533.12 → $17,533.12

Notably, on my original W-2, Box 12a was Code W, and Code DD was in Box 12b. 

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The only change I actually needed was to Box 12a, Code W, to show that I did not over-contribute to my HSA by ~$3,949.

Instead, my W-2c forms now show an increase in income and a change to my Code DD amount, entered in what appears to be the wrong box (12a instead of 12b).

The Bottom Line: I'm not sure where to go from here, and I'm (clearly) not a tax expert. Any help on the following would be appreciated: 

1. Are W-2c changes entered cumulatively, or does the most recent one supersede all prior corrections? That affects what changes I need to ask for.
2. Should I request a completely new W-2, or can a third W-2c fix everything? 
3. Should I ask the payroll company to void both prior W-2cs and issue a single, consolidated corrected W-2c, rather than trying to stack corrections myself? 
4. Since W-2s and W-2cs are also filed with the SSA, is there a way to confirm which version the SSA/IRS has on record, in case it differs from what I end up using to file? Is there any reason to worry that the correct numbers will not be reported via the W-2c? 
5. Lastly, what are my options if the payroll company does not correctly report or will not issue a third W2-c?