Incorrect totals (percentage) - SAP BW

Hi, I am trying to make a BW report using a calculated column/formula to show as a percentage; this works perfectly for the line item level, but when Totals is added to the AfO report, it is taking an average of the percentages in column 4 as below. What I would like to happen is for it to use the total value for column 1 and 2 (210 and 185) to get the correct (weighted average?) percentage. How should I do this?