Solution : https://service.sap.com/sap/support/notes/593215 (SAP Service marketplace login required)
Key words : 
-oil-specific ale inbound processing generally ignores e1maram, ale inbound processing generally, message type message_type = 'matmas', -oil specific ale inbound, message type message_type = 'oilmat', ale inbound processing, material master mass maintenance, -oil-specific fields, leading segment e1maram, material master maintenance
Related Notes : 
       
| 576160 | MM17: BAdI implementation for append fields | 
| 567779 | Avoid changing UoM grp for oilmat. in case of existing stock | 
| 322832 | Oil fields in the material master |