No items from the purchase order have been delivered.
No items are available to add to a new Purchase Invoice.
1 or more items from the purchase order have been delivered, but there is still 1 or more items not delivered.
Only the delivered items are available to add to a new Purchase Invoice.
All items from the Purchase order have been delivered.
All items are available to add to a new Purchase Invoice, unless they have already been added to an existing Purchase Invoice.