Running Value Issue

Hi All;

I am using Running value function for the below table

I am using below running value expression

=RunningValue((Fields!new_unitrateValue.Value * Sum(LookupSet(Fields!new_mainprogrammeid.Value & "," & Fields!new_subprogrammeid.Value & "," & Fields!new_outputs.Value & "," & Fields!new_claimmonthid.Value, Fields!new_mainprogrammeid.Value & "," & Fields!new_subprogrammeid.Value & "," & Fields!new_outputs.Value & "," & Fields!new_claimmonthid.Value, Fields!new_programmeoutputid.Value, "ProgrammeOutput").length())),Sum,"Details1")

I need to show  May 14 as 2116

Jun 14 as 4232 after using the running value

But this is not the case

Any help on this is much appreciated

Thanks

Pradnya07