Cost Objects in Product Cost by Order 
In the Product Cost by Order component you normally manage your costs on the basis of lots.
You can use the following objects in the R/3 System as cost objects:
You can use production orders without a quantity structure when you are using a non-SAP production planning system. Most of the functions described in the following steps are also applicable to production orders without a quantity structure.
A collective order is a logistical linkage of planned orders, production orders, or process orders across multiple manufacturing levels.