If it's not too late, here would be my suggestion.
When I had a DP, my back 13.5 AC went out, and it was covered by warranty. I paid a little extra and had the dealer relocate the front 13.5K to the back, and then put a new 15K in the front.
I found that this combination was able to keep the coach cool all the time, especially when we were traveling in the Arizona and Nevada deserts in the midst of summer.
Out West Somewhere
2016 Sunseeker 3050DS towing 2006 Hummer H3