Functionality of External Repair/Buy or Kit-To-Stock works in DRP service
In case of subcontracting external relationship, the DRP does not create the schedule lines (despite the subcontracting schedule agreement is active into /SAPAPO/PWBSRC1) but creates PRs.
External Repair/Buy or Kit-To-Stock works with Purchase Requisitions only.
See SAP Help documentation:
"If you repair a location product externally, DRP generates a subcontracting purchase requisition for this location product. DRP transfers this subcontracting purchase requisition to SAP ERP. SAP ERP generates a subcontract order from this subcontracting purchase requisition and then returns the subcontract order to DRP."
Kit To Stock
"If you choose a location product for external kitting, DRP creates subcontracting purchase requisitions for this location product. DRP transfers these subcontracting purchase requisitions to SAP ERP, where subcontract orders are created from these subcontracting purchase requisitions and returned to DRP."
Rounding for Repair or Buy and Kit to Stock , Please refer below link.