Solution : https://service.sap.com/sap/support/notes/146761 (SAP Service marketplace login required)
Key words : 
additional key words va41, item key figure, affected key figure, system determined 'va', determine time 'va', create update rules, update rules, times 'va', determine 'vb', contract consists
Related Notes : 
       
| 1597096 | FAQ: Statistics update in Sales Information System | 
| 204130 | SIS update: Collective note | 
| 133939 | SIS: No update for contracts |