Solution : https://service.sap.com/sap/support/notes/109899 (SAP Service marketplace login required)
Key words : 
additional key words co41, attached source code corrections, collective conversion planned orders, production orders, planned order, order quantity, operations dispatched, operation quantity, production order, implement notes 44039
Related Notes : 
       
| 174538 | CO40: Incorrect order quantities in collective order | 
| 129970 | CO40: No operations in production order | 
| 94053 | Incor. component qty when converting planned order | 
| 44039 | Scrap qty calculation during collective conversion |