I just spoke to an IRS human today on the amendment extension (wait time 52 minutes).
She said the IRS adjustment for UCE (for a single person) is done by computers that look only at the Schedule 1 line 7 (old style)
and convert it to new style. (minus 10,200 or UC whichever is less).
The refund my niece got is consistent with this even though an amendment is still pending.
If you have other issues on your return that need correction, you can amend or wait for an IRS audit that may or may not ever happen.
