Solution : https://service.sap.com/sap/support/notes/840822 (SAP Service marketplace login required)
Summary : 
      In SAP systems, an issue has been identified where formulas using the SUMCT, SUMGT, or SUMRT operators produce incorrect results due to a program error. The recommended remedy involves importing the relevant Support Packages into the BW system. Specifically, for BW 3.0B, import Support Package 27 (SAPKW30B27); for BW 3.10, import Support Package 21 (SAPKW31021); and for BW 3.50, import Support Package 13 (SAPKW35013). Each corresponding support note will provide detailed information once released. In urgent scenarios, correction instructions are available, and preliminary versions of notes might be issued ahead of the official Support Package releases.
Key words : 
sumrt operators return incorrect values, sapbwnews bw sp12 netweaver'04 stack 13, 0b            import support package 27, 10 content            import support package 21, 50            import support package 13, 0b support package 27, solution bw 3, support package, sapbwnews bw3, 1 content sp 21
Related Notes : 
       
| 783254 | SAPBWNews BW Support Package 13 NW'04 Stack 13 RIN | 
| 723263 | SAPBWNews BW 3.1 Content Support Package 21 | 
| 723258 | SAPBWNews BW 3.0B Support Package 27 |