Solution : https://service.sap.com/sap/support/notes/643483 (SAP Service marketplace login required)
Key words :
cost center / activity type combination, tab coomplanningfield free_acttype_mastervalmin, allocation cost element, displays message ki501, activity type involved, activity type category, attached program corrections, create table zt811flags, simultaneous master data, cost center
Related Notes :
| 940407 | KP 26: Message KI 501 with same activity type |
| 644364 | KP06ff.: Message KI501 with same activity type |
| 620417 | KP26: Simultaneous master data change possible |
| 79634 | KP06ff.: Lock logic in manual planning |