Solution : https://service.sap.com/sap/support/notes/69653 (SAP Service marketplace login required)
Key words : 
additional key words transaction mp30, material forecast, forecast values, decimal places, solution repair, source code, program mm61wtop, prerequisites
Related Notes : 
       
| 393320 | Advice: Threshold value for rounding in material forecast | 
| 197300 | Values less than 10 not rounded | 
| 93765 | Forecast values: rounding decimal places |