Assign Invoice Dialog Box
Use the Assign Invoice dialog box to select whether to use the automatically assigned next invoice number or to enter a different invoice number for an invoice or a credit memo in Interactive Billing.
You can assign a different invoice number if the Allow Changes to Next Invoice Number check box is selected on the General tab in Billing Setup. This dialog box applies when you use either the Companywide or Project invoice numbering method.
If the Allow Changes to Next Invoice Number check box on the General tab in Billing setup is cleared, then instead of displaying the Assign Invoice dialog box, a message that says "The next available invoice number will be assigned" displays. You can click OK to assign the next available invoice number or click Cancel to return to the previous window without assigning the next available invoice number.