Solution : https://service.sap.com/sap/support/notes/79319 (SAP Service marketplace login required)
Key words : 
oracle databases read 'commited', open incoming orders quantity, user-defined structures -> note 105530, additional key words simulation, open incoming orders, formula/requirement recognizes, current customizing settings, requested delivery date, differences result depending, database commit occurred
Related Notes : 
       
| 975779 | Information: Updating key figures with VDATU | 
| 449046 | SIS: Simulation not equal to reorganization | 
| 430652 | LIS: Update into info structure different than expected | 
| 423224 | LIS: DBase SELECTS in formulas, conditions and user exits | 
| 385939 | SIS/BW: Changed data after correction reports in SD/LE | 
| 316996 | SIS:Reorg./analysis for del.itms w/out ord.ref.differ | 
| 204130 | SIS update: Collective note | 
| 174134 | SIS: Collective note - reorganization |