Subcontracting process of FERT material

Dear Experts,

We are sending the Finished product to external Vendor from service Order(PM). steps will as below,

Create Service Order with subcontracting check box >> System will generate PR with the component

Convert to PO and carry the Goods issue with 541.

Goods receipt with 101.

Here when we receive the material using 101 movement type, Material code will get changed based on the quality of the material, we may post it to Category A, B or C and accordingly material code will get changed.

We suggested to go for Material to Material transfer after GR, but they are not Ok with it.

How to handle this scenario in SAP.