Late Charge Calculation amount should be same for Draft and Final mode

Hello Experts,

When we ran the Late charge for the customer for different periods  the amounts showing in the Draft mode is showing different then inthe next month.

Say for Jun if the due date is 30 Jun for invoice 1000, the int calculated as 10, in both  Draft mode and Final mode. but when we run the Late charge for 13th Jul month for the same invoice due amount ,for draft mode it is calculating as 20 , but the Final mode calcualtes as 10.

We are looking to see the draftmode and Final mode as same for Jul month 10 , is there any possibilities?

Thanks,