The "free" hitch bar exchange program is only available for the original owner as far as I know. Any local dealers who sell the Hensley? They will usually exchange for a fee too which may be less than shipping. I have also seen others online looking to swap. Craigslist etc.
Better yet, consider buying the adjustable stinger from Pro-pride. It works with the Hensley and you'll never have to swap again. I wish I had gone this route. I've swapped 3 times in 5 years. Even though I use the free exchange, that's a lot of money in shipping.