At this point, you have to discover what form or schedule is different from what you originally filed, causing a difference of $374.
Then you go in and correct the discrepancy to remove that $374.
You have to compare forms and schedules anyway to attach the required forms to 1040-X when mailing.
The rule is, don't start AMEND unless the tax return you're working on is identical to what you filed.
Sorry, should have mentioned this in the first response.
Note: I've found that if you try to unwind/cancel an amendment and start over, TurboTax gets confused and it never recovers from that to permit a correct 1040-X.
