Solution : https://service.sap.com/sap/support/notes/62582 (SAP Service marketplace login required)
Key words : 
additional key words vprs, resetting field komp-kaend_typ, condition category 'g', vprs condition, field selection, cost condition, condition rate, billing document, sales order, symptom occurs
Related Notes : 
       
| 381348 | Using user exit, customer exit, VOFM in SD | 
| 33487 | REPRICING FOR VPRS AND PI01/2 (IV) SHOULD NOT OCCUR |