Conditional Format a CrossTab

Hello I have an existing cross-tab report that I need to do a conditional format on. In my report I have a sum of QTY Required by Day in the Summary section of the cross-tab. I also have a field call Balance on Hand on each Row. I would like to change the color for any of daily QTY required that are greater than the Balance on Hand. This is simple in a Standard Report, but for some reason Iu2019m struggling figure out how to make it work in a cross-tab. Thanks