You're not paying for both. Go with Sphere and you get S1-5. It's not the case that if you buy Sphere you must then also buy S1-5. On the other hand if you buy only the upgrade from S1-4.x to S1-5, you do not get Sphere. In that case, you'd still have to pay for Sphere if you wanted it. Obviously the better route is to go with Sphere.