Larry,
To the best of my knowledge the Attwood water heaters are not adjustable. I have read an tech article, I believe in Family Motor Coaching, on how to make the mod to an adjustable thermostat on water heaters. There is also a retrofit kit available for Attwood water heaters so you can change to an adjustable thermostat. Here is the link for the adjustable thermostat at Amazon. You will however need to determine compatibility with your model water heater.
http://www.amazon.com/Atwood-93105-A.../dp/B001BZ36HM
The hot water temp has been an issue across multiple manufacturers but is one most folks live with because using a combination of hot and cold water reduces the cycle time when the hot is used for showering.