Solution : https://service.sap.com/sap/support/notes/534380 (SAP Service marketplace login required)
Key words : 
adjusted order finish date, system displays message md487, order finish date, production end date, late requirement coverage, -schedule requirement coverage, determined production dates, -house production times, material requirements planning, lead time scheduling
Related Notes : 
       
| 640207 | MD03, MD43: Incorrect planned order dates | 
| 603487 | Matl reqmts planning: No switching to forward scheduling | 
| 441506 | Corr. to Note 434693: Reduction during lead time scheduling | 
| 434693 | Correctn for Note 406650: Reduction for lead time scheduling | 
| 406650 | No reduction during lead time scheduling |