Hi Atef,
It is not displaying based on the payment term, but the number of days. If you have e.g. 2 invoices on June 1.
If the terms of payment is Net 7, then the due date is June 8. For Net 15 it is June 16.
When you run the report on July 5 based on the invoice date selection, both will appear in the column "31-60".
When you run the report on July 5 based on the due date selection, the first one will be presented in the bucket "31-60" and the other one in "1-30"