Recently after the 3rd a/c conked out on our 07 25' FB we had a new one installed at Jackson Center. There was no 13,300 btu in stock so a 15,000 btu was installed. What a difference it has made with keeping our trailer cooler. The 15,000 should have been on the trailer when it left the factory.
I had purchased a Yamaha 2400isHC to power the 13,500 and now I have an generator which will not run my current a/c. Adding the extra btu was worth it especially dealing with the hot temperatures in Texas.