Solution : https://service.sap.com/sap/support/notes/526577 (SAP Service marketplace login required)
Key words : 
transaction 'backorder processing result', 'backorder processing runtimes', time stamp reason, backorder processing, time stamps, runtime log, terms transcations, /sapapo/bop, /sapapo/bop_result, /sapapo/bop_runtimeruntime
Related Notes : 
       
| 516007 | /SAPAPO/BOP_DELETE does not delete all entries | 
| 375193 | Backorder processing: Composite SAP note on posting |