Mixed Invoices are invoices or credit/debit memos for which you can perform both positive and negative matching to purchase orders and to other invoices.
For example, you can enter an invoice for -$100 with Invoice Type Mixed. You can match to an invoice for $-200, and match to a purchase order for $100.

To enter a Mixed invoice:
1. In the Invoice Workbench, enter a Mixed invoice Type. Enter all basic invoice information.
You can enter either a positive or negative invoice amount.

2. Match to purchase orders, and/or invoices.