sorry may be my explanation wasn't exact, payment history is working well, when adding the amount into dsb_payments table it will be shown correctly.
What I mean is: Is it possible to add an addional field to " Change Membership", for example:
membership - available now
duration - available now
plus additional field: Amount of money
possibly need to be modified in /admin/membership_assign.php and related files
so the paid amount will be enter into the additional field and will be saved automatically into dsb_payments table and it's not necessary to do that manually.
Think it would be a great feature to make it easier to handle offline payments.