Entity Health attached to Overlay

Hello! I need help with a procedure that "almost" works. It's a procedure attached to an overlay, that should show you the health of the entity you are looking at, but right now, it only works when you are the exact distance away as specified in the procedure. Do any of know how to make it so that you can see the entities health as long as you are within 20 blocks of it?

Here is the procedure: