Well, because in Glycolysis, fructose six phosphate form fructose one six bits phosphate via an irreversible step. And what that means is in Glycolysis, this step was basically a very exergonic step. And in this case, we can't simply reverse the steps of Glycolysis because that would mean we would have to input a very large amount of energy. And so for the same exact reason that we have to follow a different pathway to get from Pyruvate to phosphorino Pyruvate, to get from fructose one six bits phosphosphate to fructose six phosphate, we also have to create a completely different reaction pathway and we have to use a completely different enzyme. And that's exactly why the reaction pathways that we use is the hydrolysis of the Esther bond between carbon one and this oxygen in this fructose one six bisphosphate. So this is the reaction that allows us to basically convert the fructose one six bisphosphate into the fructose six phosphate via an exergonic reaction, an energy releasing step.