Business & farm

There is a manual option which is all you really need ... once you have completed the form 8829 in the 2019 return  then enter the carryover info in to the 2020 amended return's form 8829 ...  look in the OIH section for the  screens  below ...  do not start the 2021 return until you have completed the 2020 amendment ... if you wait the correct carryforward will be transferred automatically ... otherwise you will need to enter it on the 2021 return OIH section again.

FYI ... the carryover is cumulative ... you ONLY enter the info from the immediate prior tax year.