Lookupset and lookup error

Hi All ;

I have a table called ProgrammeOutput as below

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and Programme Profile table as below 

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i am using the code in Programme profile table as below

=LookupSet(Fields!new_claimmonthid.Value, Fields!new_claimmonthid.Value, Fields!new_programmeoutputid.Value, "ProgrammeOutput").length

this should return me (in programme profile table )

5 for July'14 Business Assist but it returns 26 in programme profile table

Any help much appreciated

Thanks

Pradnya07