Incorrect Column Totals

Hello,

I have a matrix table with periodic values for revenu, cost, gp(calculated) and gp% (calculated) coming from an excel. Looking at the rows for each period, the gp and gp% are correct, but looking at the column totals, they are correct, except for the gp% where the total becomes the sum of the lines instead of the % for the Total row (gp / revenue). So as there are many lines teh total % becomes astronomical. Can this be handled somehow?