There are less expensive places with regards to the hourly labor rate to have this done. It's all a matter of doing your due diligence and research. A friend of mine had his done shortly after I did at Iron Horse RV located in Texas. It turned out a couple of hundred dollars cheaper due to the lower labor rate however, I would have spent more than that just getting to that shop in fuel plus it wasn't on my route from Florida to Alaska.
The most expensive place I found was Alliance Coach in Wildwood Florida. They started at $3500 for the change-out.
Regarding labor rates, I just had my Aqua-Hot system repaired at Karens RV in Anchorage, an authorized service center for Aqua-Hot service. Labor rate $129 per hour. Repair bill, $1233. 3 hours labor and the rest in parts.
Dr4Film ----- Richard