Presumably you have not yet completed applications to these programs because they are a lower priority for you. If you have a high hit rate on the places you did apply, then there is probably no reason to spend the money applying to lower priority schools. If you are not getting many interview invites, then applying to lower priority schools makes more sense. Your hit rate at those schools may not be any better, but you will have more interviews in aggregate, and a better chance of getting in somewhere.