If you place it above the guides, it will normalize the guides. If you place it above the hairs, it will normalize the hairs. The order matters but it depends on the results that you want. 

Have in mind that this node will be recalculated at every frame, which may cause hair flickering on some cases, because it will normalize all the strands on each frame. You may need to bake(Right click>Bake) this node before rendering.

Jeordanis Figuereo (Product Designer. EPHERE Inc.)