Solution : https://service.sap.com/sap/support/notes/619826 (SAP Service marketplace login required)
Key words : 
terms deleting zeros reason, data records read, separate batch job, separate job, existing records, selected records, deleted records, fact tables, support package 31, support package 15
Related Notes : 
       
| 1470209 | BW report RSCDS_NULLELIM on InfoCube without time dimension | 
| 1323057 | Program RSCDS_NULLELIM does nothing to BW aggregates | 
| 1224631 | Program RSCDS_NULLELIM and Float-Keyfigures (Type FLTP) |