Solution : https://service.sap.com/sap/support/notes/750554 (SAP Service marketplace login required)
Key words : 
sets starttime s2   {      wait time, <-- start record 1 -->   starttime s1, initial starttime -->   {      wait time, navigations   }   starttime s2, time stamp reason, current time stamp, data displayed   ----------------------->  record, previous data record, bw statistics record, function module called
Related Notes : 
       
| 723259 | SAPBWNews BW 3.1 Content Support Package 17 | 
| 723192 | SAPBWNews 3.0B Support Package 23 | 
| 693495 | SAPBWNews BW Support Package 05 NW'04 Stack 05 RIN |