I appreciate your reply. My custodian actually didn't refer to it as a mistaken distribution; they have a different form for that, and that form specifically states that it's not to be used for erroneous excess distributions. The form they sent me was their standard contribution/deposit form. So I will fill that out and send it along with a check. I will also include a nice letter explaining the situation and asking them not to report it as an additional contribution.
And yes, I realized too late that I should have just let TurboTax figure out any excess instead of trying to do it myself. Lesson learned!
