Some customers may require invoices to be processed periodically, so that all deliveries due for billing by a certain time are put into one collective invoice.

To fulfill this requirement, a billing schedule must be defined for the customer:

• A factory calendar which contains special rules instead of working days must be created. These special rules refer to the days on which billing should be carried out. If, for example, an invoice is to be issued every last working day of the month, then this day must be entered as "valid from" day and "valid to" day. This day must be the only day defined as a working day in the calendar for each month.
• The ID-number of the factory calendar must be specified on the billing screen of the payer's customer master record in the Billing schedule field.

When a sales document is created, the system copies the invoice date from the factory calendar and enters it into the relevant document as follows:

On the next billing date determined by the factory calendar, the system selects all sales orders and deliveries and puts them in a billing due list. They can now be billed.

As a result of the ID-number of the factory calendar defined in the customer master record, all sales orders or deliveries for that customer over a particular period have the same billing date, and they can be combined in one collective invoice.

The following figure shows how the system proceeds if a billing schedule has been defined for a customer.

For further information on creating a factory calendar for invoice dates, goto the online Implementation Guide (IMG) and view the Maintain calendar section under Global settings.