Solution : https://service.sap.com/sap/support/notes/63630 (SAP Service marketplace login required)
Key words : 
additional key words schedulingbasic dates, attached source code corrections, incorrect order finish date, planned end time, expected date, date limit, begin time, day deviates, previous day, transaction mf50
Related Notes : 
       
| 80344 | Basic dates or operation dates on the wrong day | 
| 46237 | Consulting: determination of the order dates |