I think (but only the manufacturer knows for sure) that the limiting reagent in these reaction is the compound that gets oxidized, the oxalate ester. I call it the fuel, analogous to the reduced carbon compounds in combustion that gets oxidized by oxygen. The phenyl oxalate ester fuel is, in general, the most expensive reagent in the mix besides, and so economics will out and the cheaper oxidant is probably added in excess. So when the fuel has been oxidized, the excited product created, and its energy transferred to the dye, added oxidant won't get you anywhere. Some of the mechanistic studies have suggested that the ratio of oxidant to fuel should be 1:1. So the excess I'm describing may not be much.