Solution : https://service.sap.com/sap/support/notes/164682 (SAP Service marketplace login required)
Key words : 
material requirements planning planning time fence, symptom material requirements planning generates, additional key words md01, periodic lot-sizing procedure 2, periodic lot-sizing procedure, planning time fence, lot-sizing procedure, note corrects precisely, lot size > 1 3, lot size = 1
Related Notes : 
       
| 331976 | Lot size acc. to flex.period lgth->incor. dely date | 
| 198871 | MRP: Procurement proposal in planning time fence | 
| 120546 | MRP: Procurement proposal in the past |