One Invoice Per Packing Slip
Select this check box if you want the system to only include one packing slip number on an invoice. Clear this check box if you want the system to refer multiple packing slip numbers on an invoice.
This field is enabled when you select the Print Packing Slip On Invoice check box.
When you select this check box on the Customers or Multi-Site Customers form, you must select the Create from Packing Slip check box on the Order Invoicing/Credit Memo form in order to print invoices for this customer.