POS Invoice total commission in POS register is incorrect

We are adding a total commission to the POS invoice via POS (added total commission as an additional field under POS settings). For example, if we enter 500 as the total commission, and generate the POS register report, the total commission shown for the corresponding POS invoice is incorrect.

Total Commission shown in POS register report:

What’s the reason to show the total commission as 500.01 instead of 500 here? Also, note that the total of commissions is shown as 0.