Solution : https://service.sap.com/sap/support/notes/39327 (SAP Service marketplace login required)
Key words : 
additional key words volume rebate, vendor master record, specific vendor data, purchasing data, control data, subsequent settlement, general level, purchasing organization, purchase order, initial screen
Related Notes : 
       
| 40147 | Collective note: Subsequent settlement (Purch.) Release 3.0 |