Spray 5-quart slow cooker with cooking spray. In slow cooker, beat milks, melted butter, mustard, salt and peppers with whisk. Add macaroni and 3 1/2 cups of the Cheddar cheese, the cubed cheese and Parmesan cheese. Cover; cook on Low heat setting 1 hour. Stir well. Cover; cook 1 to 1 1/2 hours or until pasta is cooked, but not mushy.