What was stated above is 100% correct.
Just to clarify: the additional attacks aren't wasted, because you roll once on the injury table for each successful wound. Thus, if your first wounding attack knocks down the opponent, the second wounding attack has a chance to stun or OOA the opponent. As all of a model's attacks are rolled simultaneously (except in odd cases such as a saurus's bite), this should not really be an issue as there isn't really a 1st, 2nd, 3rd... attack. Rather, all would hit, wound, and injure simultaneously.