Yes, you got the exactly right. The REAL difference is that the ATM form is missing the date in a column for part II. The IRS schema for e-filing requires that now. TT need to fix their form so that the date gets added for the ATM form when doing simplified. It can't be that hard to fix, especially since they could just read this thread and figure it out.
If your failure is with the IRS "parsing" your form (rejected in 4-5 minutes), then the IRS did not read any data and no amended return is needed yet. (besides, wouldn't TT tell you that an amended return is needed and not ready?)
TT is not handling this well. Not quickly. I am very glad I made the decision to file a return with a "typo" that eliminated the AMT form (but kept the same refund amount). oops. Got my refund. The new stimulus check is arriving this week. I'll amend the return to fix the typo. If I had waited or mailed, I would not have my money. I would not be getting any stimulus money because my 2021 income just might be above the threshold.
