I haven’t been a CPA for as long as Nothar, so I don’t have as much experience. If someone has seen this exact scenario play out at least 100 times, then who am I to argue. My only concern is that it wasn’t the same scenario. As I’ve said in my first post, what Nothar describes happens when a carryover is overstated, but there is no tax impact in the year that the mistake was made.
Here’s an example. Let’s say that a mistake is made on the 2010 tax return. Charitable contributions were overstated, but the taxpayer wasn’t able to deduct the full amount in 2010, due to a limitation. Consequently, some of the contributions get carried over to 2011. Let’s also say that if the taxpayer reported the correct amount of contributions, he still would have had a carryover, but it would have been smaller.
When the 2010 return is audited, and the mistake is found, there is no tax impact in 2010. No additional tax is due, and interest and penalties don’t apply. The audit then gets expanded to 2011, and the change is made to the carryover.
For 2011, the amount reported as a carryover gets reduced. If the full carryover was not used in 2011, then the tax impact that year is smaller than if the full carryover is used. If by using the carryover in 2011 taxpayer received a tax benefit of $500, then this is how much additional tax he’d owe for 2011. Interest would be computed from the due date of the 2011 tax return, and penalties might be applied. That’s what Nothar describes, and I agree that this is what happens for carryovers.
This is not the same situation as the one described in the OP. Refund applied to the subsequent year is not a carryover. When the 2010 refund is applied to the next year, the IRS credits this amount to your 2011 account. Even before you file the 2011 return, this amount is already on your record for 2011. If you call the IRS and ask about your 2011 account balance, they’ll say you have a credit of whatever. They keep track of this number. When you put that amount on the next year’s return, it’s correct, because it matches what the IRS has in its system. During audit, this number should not be changed.
Here’s a .pdf of a Revenue Agent Report (RAR). This is what the IRS uses to compute additional tax liability. Lines 73 through 77 of the Form 1040 aren’t used on the RAR. This is why it’s irrelevant during the audit whether you chose to get a refund right away, or to apply it to 2011. The auditor would not expand the audit to the 2011 tax return. The mistake would be fixed at its source.
Based on the OP, the last number on the first page of the RAR would be $500. The second page of the RAR would show interest computed from the due date of the 2010 return. I’ve seen enough RARs to know that the auditor has to actively specify whether the penalty applies, but interest is added automatically. In my (limited) experience, the only time that interest gets removed is when IRC Section 6404 applies. If Nothar or someone else lets me know what other code section would apply in this case, I’d appreciate it.