In Pokemon Diamond, how exactly does Exp. Share effect EV distribution?

It divides the number of EP you receive when you defeat a Pokemon to the number of pokemon you used in the battle plus the pokemon holding exp. share. For example, say you get 1200 EP from defeating an Onix. If you only use one pokemon without exp, it and the pokemon with the Exp share would both get 600. If you did use the pokemon w/ exp share, then that Pokemon would get an Additional 600 points.