Additive Cost Caputuring in Sub Contracting Process

Dear Experts,

We have Raw Material A with price Re.100, and sent to subcontracting become the Semi Finished B Re.150(100+50Sub Contract charges).

Here how I can load this Re.50 as subcontract changes? Because no routing and BOM is exist for SF B.

Is Additive cost will work for this? If it is pls help me how to deal with this....

Thanks in advance,

Regards,

Balaji Bhonsle.