The debit frequency regulates whether charges related to a customer order are invoiced with any backorder or all at the same time. These can be order charges, item charges or service charges.
When backorders are invoiced, the debit frequency is checked to determine if any charge should be made again. If the charge is debited only at the first delivery, it is calculated on the entire order. If it is to be debited for each backorder, it is calculated accordingly.