BOM OF ROH Material

Dear Expert

We are purchasing material "X" from vendor & in standard cost run system considering RM cost .

Due to non availability of material " X" the client decided to manufacture it from subcontractor. then he maintain special procurement key 30 & BOM for same material. so the cost of component and sub contract cost will be capture during standard cost run.

means material"X" ( MType-ROH) can be procure from market or can be process at subcontract.

My question is " is this process of maintaining BOM For ROH is wrong practice "? is their any Limitation?

with regards.