Issue on getting the similar functionality for assosiation in c8 as in imprompt

[ranne_78]

Hi guys,

We migrated impromptu7.2 catalogs and reports to cognos8BI.
For some reports in impromptu they associated for some columns to the particular column.
Let us say
In Impromptu Report they mentioned as follows

Total(Fulltruck-Amount) associated with Natlparent(Automatic) 


TO achieve the same functionality we are trying to create
the following expression in expression window of that particular dataitem.

(Total(Fulltruck-Amount) for Natlparent)

to get the Autimatic aggregation we specified in  Aggregation and rollup aggregation to Automatic.

still we are not getting the exact result set as in impromptu report.

I tried to get exact results as in impromptu by changing aggregation to none/calculated/total/automatic.
But no use.
Any help pls.