PR is cretaed manually or automatically generated through MRP.
This this assigning of Source is done by ME57 and i want to pick on quantity percentage basis.
Like Ex - PR generated for 1000 Material and for this material source should to picked depending on percentage basis.
quota arragement and source list maintained for 1000 quatity as
400 - Vendor X
150 - Vendor Y
550 - Vendor Z
How the system will be picked the vendors for the the PO generation with the sources on % basis which is maintained in Quota arrangement.
Explain me the flow