Solution : https://service.sap.com/sap/support/notes/519317 (SAP Service marketplace login required)
Key words : 
source code correction, transactions mm02, run forecast, mpxx rounding, rounding strategy, terms forecast, mp33 reason, data definitions, solution implement, implemented note 502897
Related Notes : 
       
| 393320 | Advice: Threshold value for rounding in material forecast |