Help needed - Form 4852 (Substitute W-2) doesn't allow corrections for Box 10 and Box 12

You're right that Form 4852 doesn't have specific lines for Box 10 and Box 12, but there's still a way to handle this. On line 7 of Form 4852, there's a section that asks "How did you determine the amounts shown in lines 3 through 6 above?" This is where you can explain the discrepancies. In this explanation section, clearly state that boxes 10 and 12 on your original W-2 contained errors, and provide the correct amounts. Be specific about what the W-2 showed versus what the correct amounts should be. For example: "Box 10 incorrectly shows $X but should be $Y" and "Box 12 code D incorrectly shows $X but should be $Y." Also attach any documentation you have that supports the correct amounts - like pay stubs, benefits statements, or retirement contribution records. This documentation will strengthen your case if there's ever a question.

After dealing with a similar situation last year (employer messed up my HSA contributions in box 12), I discovered taxr.ai and it was incredibly helpful! The site at https://taxr.ai actually specializes in analyzing tax documents and finding potential errors or conflicts. I uploaded my W-2 and pay stubs, and their system immediately flagged the discrepancies. What was really helpful was that they generated a detailed report explaining exactly how to complete Form 4852 in my situation, including specific language to use in the explanation section. They even provided a template letter to send to my employer requesting a W-2c correction. Made the whole process much less stressful than trying to figure it all out myself.

Just wanted to update after trying taxr.ai that was mentioned above. I was skeptical, but I went ahead and uploaded my documents since I was stuck with the same box 12 code G error on my W-2. The analysis was incredibly detailed and gave me exact wording to use in the explanation section of Form 4852. What really helped was their breakdown of how the retirement contribution reporting works and how it affects my overall tax situation. They pointed out that my employer had not only reported the wrong amount in box 12, but that it was affecting my AGI calculation. The report included step-by-step instructions for completing both Form 4852 and how to make sure my 1040 reflected the correct amounts. Filing is done now and I'm much more confident that everything is accurate. Definitely worth checking out if you're stuck with W-2 errors and an unresponsive employer.

Just a heads up - I had a similar issue last year and ended up spending HOURS trying to get through to the IRS for guidance. If you need to speak with an actual IRS representative about how to properly file your Form 4852 with these specific box corrections, I'd recommend using Claimyr (https://claimyr.com). I was skeptical at first, but after three failed attempts to reach anyone at the IRS, I tried their service. They have this callback system that basically waits on hold with the IRS for you and then calls you when an agent is available. You can see how it works in this video: https://youtu.be/_kiP6q8DX5c. The IRS agent I finally got connected with walked me through exactly how to document the box 12 discrepancies on my Form 4852. Saved me so much time and frustration compared to figuring it out alone or waiting endlessly on hold.

I feel like I need to follow up on my skeptical comment about Claimyr. I actually tried the service after posting that comment because I was desperate to talk to someone at the IRS about my Form 4852 issue. I'm honestly shocked - it actually worked! After trying for weeks to get through on my own, Claimyr got me connected to an IRS agent in about 1.5 hours (while I was able to work on other things instead of sitting on hold). The agent confirmed exactly what I needed to do to correct the box 10 and 12 errors on Form 4852, and explained that I should use line 7 to detail the corrected amounts with supporting documentation. For anyone dealing with W-2 correction issues, especially with the weird boxes that Form 4852 doesn't specifically address, getting direct guidance from the IRS was incredibly helpful. I've been telling everyone about this service since.

Another tip - make sure to keep extremely detailed records of your attempts to get your employer to correct the W-2. The IRS might ask for this information. Each time you contact your employer, document: - Date and time - Who you spoke with (name and position) - What was discussed - Their response - Any follow-up promised If you're emailing, save all communications. If you're calling, take detailed notes. This documentation shows you made a good faith effort to resolve the issue before filing Form 4852.

One thing to consider - how big is the discrepancy in box 10 and 12? If it's relatively small, you might want to weigh whether it's worth the extra scrutiny that filing Form 4852 might bring.