Solution : https://service.sap.com/sap/support/notes/406650 (SAP Service marketplace login required)
Key words : 
additional key words md01, -house production time, resulting lead times, attached program corrections, order finish dates, actual requirements date, required requirements date, lead time scheduling, material requirements planning, late requirements coverage
Related Notes : 
       
| 640207 | MD03, MD43: Incorrect planned order dates | 
| 603487 | Matl reqmts planning: No switching to forward scheduling | 
| 534380 | No adjustment of order finish date after lead time schedulng | 
| 441506 | Corr. to Note 434693: Reduction during lead time scheduling | 
| 434693 | Correctn for Note 406650: Reduction for lead time scheduling | 
| 359288 | Incor.available qntity for scheduled planned orders | 
| 207572 | MRP: Plnd orders w/ basic start > basic finish |