Solution : https://service.sap.com/sap/support/notes/708487 (SAP Service marketplace login required)
Key words : 
transaction se37 -> function module cs_md_kdst_stzu_lesen change -> import parameter -> insert, transaction se11 -> structure kast change -> insert, component component typevbeln        kdaufvbpos        kdpos, activate changed structure kast, highest internal bom number, function module cs_md_kdst_stzu_lesen, import parameter ecslid, import parameter ref, expand structure kast, tcs41-cslid                        xactivate
Related Notes : 
       
| 819074 | 351451: Incorrect dates after MRP run | 
| 814644 | 351451:MRP selects order BOM with incorrect use | 
| 338148 | MRP generates WBS BOMs with incorrect BOM usage |