The zones are unreliable at best. I've tried 3-2 and 2-3 and both place the wrong players in the wrong positions on the floor. There is no reason that an inside defender should be guarding outside shooters on multiple occasions. The only solution is to build each defender the same way, and use the little bump you get to ID or OD from the chosen tactics. The sim is just not advanced enough to recognize that a zone is designed so you don't have to switch assignments. Each player stays home.