Solution : https://service.sap.com/sap/support/notes/1033885 (SAP Service marketplace login required)
Key words : 
account assignment detail, prerequisites cost center, ebp solution implement, symptom description behaviour, values starting, terms cost_ctr, conversion_exit_alpha_output reason, alpha-converted, /3 plug-in856914, attached correction
Related Notes : 
       
| 1140770 | FAQ: F4-Help Cost Assignment | 
| 982263 | Changes made in account assignment screen 1000 | 
| 892702 | fund center description not retrieved | 
| 857326 | Plug in:Cost Assignment search returns incorrect description | 
| 856914 | Cost Assignment search returns incorrect description |