After you file

TurboTax Online 2020 is seriously flawed (see other posts on the forum about this).

It won't let you change/correct 1040-X line 18.

So if IRS adjusted your refund, then the refund shown on 1040-X is not accurate.

 

To get a completely correct Form 1040-X you'd have to fill out the form manually and file on paper.

you can get 1040-X in pdf-fillable format from IRS.gov.

 

From this you can see that  the TurboTax guarantee means nothing.