Solution : https://service.sap.com/sap/support/notes/68904 (SAP Service marketplace login required)
Key words : 
additional key words fv45efep mv45af0b beleg_sichern xvbep_zuordnen correction deliveryschedule line, prerequisites solution schedule line deletions, great confusion due, fv45efep solve, routine xvbep_zuordnen, schedule lines, sales order, considerable deterioration, large number, change documents
Related Notes : 
       
| 129470 | Incoming orders for component suppliers: Alternative update | 
| 109189 | SIS comp. supplier:Incoming order may be too high | 
| 101342 | Performance during rescheduling | 
| 83501 | Incorrect requirements records (VBBE) |