Center outward??
Only way that could happen I'd think is very low camber and you constantly turn hard so your tires go way positive camber or your toe is really jacked up. Extremely toed out I believe? 18.5k isn't bad though haha.
One more reason why the stock eccentric bolts suck! Can't change settings on a Z if the bolts are locked out and can't slip! Good thing I have them.