i've said this elsewhere but i'll say it again. UCI does two rounds to fill up their class. one in the fall and one in the spring. so if they sent you a secondary it is because they liked your application and a) haven't filled up as much of their class as they would like to or b) want more variety in the incoming class or c) d) e) f) any other # of reasons. so go ahead and fill it out. you never know what could happen.
-mota