Restrained materials checkbox only affects jobs that are make to order when scheduling runs?

Is it normal for the scheduling engine to completely IGNORE the constrained material checkbox IF the job is setup as make to stock? That is what we are seeing on our system. If the job is Make to Order, it schedules correctly with constrained material. Is this a BUG? Epicor has been very quiet on responses on this to us. Most of our jobs are make to stock so the scheduling system is useless to us at the moment.