Except they are further away from the center, or what was the center, because you're moving the goal post. Only by adding Lebanon and Waynesville is Springfield the 'center' of the conference. It was not the center of the conference before. Lebanon and especially Waynesville were well outside of the geography of the COC at the time they were added.
Waynesville only fits from the perspective of someone in Springfield because for them at least, it's not any further than places they were already going.
Consider this - the COC adds Pryor, OK and Claremore, OK. If that happened I'm pretty confident the good people in Nixa would be up in arms. They would say those schools don't fit, they are too far away and one of them isn't even good competition. Then Joplin could say sure they fit, they are the same distance from the center of the conference (us), just in a direction that is unfortunate to you.