Help with Suburban Hot Water Heater.

I have a 2020 Rockwood Mini Lite 2109S. This past week went to the Sierra's at an elevation of about 6500 ft. The Hot Water heater would not work on propane and I tried everything. Finally had to use the electric side and had hot water. Looked at the manual and it states that the propane will only work at 4500 ft or lower and I would have to have it derated. Has anyone done this and if so how do you do it? The older style had a adjustment at the tube but this one does not. As soon as I got home to an elevation of 1500 ft I tried the hot water heater and she fired up in a second. So I need some help. Thanks Ed

Also, the oven would not lite. all the burners worked, the heater worked and I just had the tanks filled with propane. Are these related?

model on hot water heater is SW6DELC don't have one for the stove.