Only appears for subcontracts. If you will be shipping parts to a subcontractor, you must report the shipped quantity in this field. In this case, you should not report any other quantity. All other fields, except the field in which you indicate the date on which the shipment will take place ("Shipped on"), are greyed out.
To the right of this field you will see if any parts have already been shipped to the subcontractor for this operation ("At supplier").