Solution : https://service.sap.com/sap/support/notes/1093866 (SAP Service marketplace login required)
Key words : 
prognosis correction creates accountsand determines, goto -> text elements -> text symbols, prognosis adjustment background job, system calculates incorrect values, creates released prognoses, calculates correct values, wrong calculation base, changed percentage rates, support package fsri60070010, call transaction se11
Related Notes : 
       
| 672255 | Shortened fiscal year/changing fiscal periods |