Grand total from subtotals

Hi There,

I want to calculate Grand total from subtotals , we structures in row and columns.

Under structure  we have couple of characteristics ( Income , staff cost etc.)  and we have separate info object Cost Element .

I am getting subtotals of (Income and staff costs etc) ,but I want grand total from subtotals at bottom of the report . if I use formula  to calculate grand total from subtotals , I am getting Grand total along with cost element .  I like to see only grand totals at the bottom of the report , not with cost elements.

Any input in this .

thanks

Hari