Solution : https://service.sap.com/sap/support/notes/118924 (SAP Service marketplace login required)
Key words : 
additional key words pos entry, check box 'parallel posting', sap retail pos interface, store-related mass data, define processing mode depending, partner profile inbound processing, inbound partner profiles, operative data accrued, solution short overview, load distribution mechanisms
Related Notes : 
       
| 213546 | HPR collective note: POS inbound | 
| 116784 | Performance improvement for the POS inbound | 
| 113107 | Double update of IDocs with report RBDAPP01 | 
| 89471 | Collective note ALE input processing | 
| 78935 | Duplicated update of IDocs in ALE Inbox | 
| 78757 | SET UPDATE TASK LOCAL | 
| 74777 | ALE/EDI:BD87 IDocs can be imported several times | 
| 70961 | EDI/IDoc: Inbound sporadic errors DUPREC EDIDS. |