Solution : https://service.sap.com/sap/support/notes/198835 (SAP Service marketplace login required)
Key words : 
additional key words rm06ellb, executing transaction me2o, sc stock monitoring, stock monitoring, sc = subcontracting, purchase order, pogram error, performance problems, subcontracting, performance
Related Notes : 
       
| 458938 | FAQ: Subcontracting stock monitoring list, transaction ME2O | 
| 458512 | ME2O Performance during selection via assembly | 
| 360019 | ME2O: Performance during SC Stock Monitoring III | 
| 337828 | ME2O: Performance during SC Stock Monitoring II |