Solution : https://service.sap.com/sap/support/notes/510344 (SAP Service marketplace login required)
Key words : 
attached source code, sales order data, sales information system, pos data reason, order exists, system calls, pos interface, billing update, billing document, collective runs
Related Notes : 
       
| 204130 | SIS update: Collective note | 
| 186019 | Performance of billing update | 
| 174134 | SIS: Collective note - reorganization | 
| 167092 | Statistical setup for value contracts |