Asking for 1/1/2021 balance to calculate an average loan balance. Beginning principal plus Ending principal divided by 2 is average used by TT in there calculation of average loan balance. As I said before, if just made regular scheduled payments or same amount per month this should be close to actual average principal amount.
Beginning = Loan at beginning of Year (1/1/2020 principal on Original Loan)
Ending = Loan at beginning of next year (1/1/2021 principal on Refinanced Loan)
