- Since you have I-485 pending, you may be considered in AOS, although you have valid H-1. When you use EAD, you will lose H-1 and be totally AOS. You don't have to change to H-4 so as to use EAD, and doing so does help neither.
http://blog.wenxuecity.com/blogview.php?date=200710&postID=20710