My answer is based on the 1040X instructions for column A and the years I taught tax prep classes on the subject. The IRS rule is : Column A needs to reflect the must current information which is the info off the original return or as corrected by the IRS. So since the IRS is making the correction this year getting column A corrected to reflect the unemployment change but to not add the credits before amending the return could be problematic since column B will not be correct OR column A will be wrong because the TT program computes credit changes automatically when you correct the income... hence "messy".
This is a very unusual situation this year that has affected millions of returns and the IRS is making this up as they go so who knows what they are going to do ... it's a wait and see. Post back if your nieces column A is incorrect and let us know which direction the IRS takes for this situation (and PPS you know very well they can accept the efiled amended return "for processing" but then decline it in processing or return it thru a notice in the mail )... who knows if they will make the adjustment themselves or send out millions of notices asking for a correct 1040X. It is going to be a long bumpy road I fear.
