Solution : https://service.sap.com/sap/support/notes/899980 (SAP Service marketplace login required)
Key words : 
multiple customer requests based, dependent document flow record, calculation takes place, ofamng = vsmng - erlmenge_f, erlmenge_f invoiced quantity, open order quantity, open delivery quantity, oaumeop = olfmng + ofamngolfmng, mcinf_update_all form routine, lv45vffa include program
Related Notes : 
       
| 413292 | FSD:Scheduling agreemt - incomplete FRC in Cash Management | 
| 81335 | Incoming order for sched. agreements not correct |