By leaving the car wet after the first wash you're decreasing IronX's effectiveness by just a bit. You don't have to completely dry it, but you should at least use the "flooding" method to channel most of the water off the car.
Also, you've got the "rub in with sponge" and "wait 5 minutes" steps backward. You'll want to wait 5 minutes (or longer, just don't let IX dry) and then go over the vehicle with a damp wash sponge or mitt (rinse after each panel just like while washing) and then do your final rinse.