When I undid my excess Roth contribution, the custodian (Vanguard) did the actual calculation of the amount to be returned -- my excess contribution and the amount that was earned by it.

I first explained my problem on the phone, then they did the calculation and returned the amount to me. At (next year's) tax tame, I got a form showing my income on the basis of this excess contribution.

I didn't have to do any calculations or file any extra paperwork. (Well, now that I think about it, there was probably a form from Vanguard where I wrote the dollar amount of my excess contribution.) But they took care of everything. For me, it was painless.

If it's in nay way a problem for you, then my guess is that you're making it into more of a big deal than it has to be. The custodian should take care of everything.

--SirTas