Project Production Orders

In our business mapping, we have projects divided into site materials(item requirements) and production orders. We can see all the functionality working fine with site materials (item requirements) such as committed cost, cost control, cash outflow etc.. but it never consider project production orders until we end it. My question is since the project production orders are linked to the project the consumption of bom and route hours should be considered as WIP of the project, so the purchased orders for that project production orders also should be considered for committed cost and other cash outflows. I am not very sure whether my understanding is wrong or ax 2012 r2 cu8 is limited to those functionalities. Even the wbs cost tracking also not considering the project production order wip.