Water Heater Too Hot

I have a new Suburban SW6 DE water heater. It has the electric element as well as gas. I never leave the unit on unless I am about to need hot water. I control it by the breaker switch on the inside coach electric panel and only use it in electric mode. The water is extremely hot when the heater is allowed to heat up for even a little while, 30 minutes or so. It is so hot, that to take a shower you have to cut way back on the hot water and run full cold water. This not ideal when you already have poor water pressure. I also am concerned about PEX pipe plumbing connection failures when the temps are very high. I am sure I will get water intrusion soon enough, I don't want to accelerate that process.

I called Suburban today. They said that none of their electric models have an adjustable thermostat. They said the water should be 130 degrees and if it is not in that range the unit is defective and should be serviced. I asked where to measure the temp and they said to hold a bowl with a thermometer in it under the pressure relief valve and open it to fill the bowl. (I guess they didn't run that one by their liability lawyers)

One odd thing is that the little safety sticker attached to the unit, you know the one that shows someone burning their hand, says: "Temperature limiting valves are available, see manual". The manual has nothing about that and Suburban did not know what that was about.

I will measure the temp soon, but was just curious if any of you have water hotter than you would like. Also, is there a competitor to Suburban that does offer an adjustable thermostat?

thanks very much,