Actually.....Norcold/Dometic/Suburban/Atwood (fridges/water heaters/furnaces) have some sort of a statement concerning 'derating' of LP appliances above 4500' elevation.
Some posters HAVE had issues with mainly water heaters main flame staying lit when in high elevations. Having to keep compartment cover open in order to get/keep main flame lit.
Suburban does have a 'high altitude kit' for their water heater. It is composed of a smaller main gas orifice. Above 4500' change it out and then you have to go back to OEM orifice when below 4500'
We FT'd for 7 yrs. and been in many high elevations GCs and did not experience any problems with propane flames lighting off/staying lit. The flames were different but not a problem.