Solution : https://service.sap.com/sap/support/notes/423224 (SAP Service marketplace login required)
Key words : 
fill individual key figures, -defined form routines, current order number, -called consistend read, development/test system, simulation work correctly, key figures, sales order, dirty read, production system
Related Notes : 
       
| 381348 | Using user exit, customer exit, VOFM in SD | 
| 337037 | LIS: Formulas for specifying characteristics | 
| 204130 | SIS update: Collective note | 
| 174141 | SIS: Collective note - Customizing | 
| 79319 | SIS: Diff. between online/simulation/analysis/reorganization |