WIP for co-products is always valuated at actual cost. The system valuates WIP using the actual costs posted to the order item, less the credits from goods receipts.
Valuating WIP at target cost requires that the order item has a settlement rule with settlement type FUL (full settlement). The system derives settlement type FUL from default rule PP1 (Production Material Full Settlement), which the user has specified in the order type.
If a manufacturing order including co-products uses settlement type PER (default rule PP2), you cannot determine WIP for it. If you are using a cost object hierarchy with co-products, you cannot form any WIP because you can assign only periodic manufacturing orders to a cost object hierarchy.
The calculation of WIP depends on the status of the manufacturing order. The system continues to calculate WIP for the co-products until the header of the manufacturing order has the status DLV (delivered) or TECO (technically completed). The manufacturing order is only assigned the status DLV when all order items have been delivered. When the order has the status DLV and TECO, the WIP calculation function cancels any WIP from the previous period.
To see whether particular order items have been delivered, access the material list from the process order. From the materials list, access the detail view and look at the Delivery Completed (final delivery) indicator.