This new feature to copy the Sets , has nothing to do with the existing feature of fulfillment set at the order header level , but it do results in some issues/error is not take care properly.
For this new feature Oracle has provided 2 additional checkbox in the Copy Order Form.
1. Fulfillment Set
2. Ship /arrival Set
By default these will be unchecked and also if user is not copying the Order line then these 2 check boxes will be disabled.
Copy to Create New Order
Now when user creates a new sales order by copying the existing sales order, New order will have all the sets copied from the original order and these sets will have same name in the new order as that in the Source Order.
Copy lines (with sets) in already existing Sales Order
If customer try to add the order line/group of lines (with set) in an existing sales order and if the destination order doesn’t have sets with the similar name as that of the set in the source order then the sets copied as is from source order to destination order.
BUT if the lines from the source order has the same set name as that of the set in the destination sales order , then system will add the line/group of lines from source Order to existing sets in destination sales order ( Please note that Set in the destination order should be open), But in case Destination order has same set name as that of the source order , but the set is close then system will throw an error message and will not copy .
Please Refer My below Presentation on Same for More Details.