Running Out of Hot Water

[Montana_350]

I traded a 2002 Trail Cruiser hybrid for a new Montana Moutaineer 310 BHS this year. Both have 6 gal. DSI hot water heaters. The Mountaineer even has the electric/gas hot water heater. For some reason, the hot water doesn't last as long in the Mountaineer when taking a shower. In the Trail Cruiser, one person could take a reasonable shower without running out of hot water. With the Mountaineer, a single "military" shower is all you get before running out. The recovery time is less with the gas and electric on, but you would think 6 gallons in one would last as long as it would in the other. The only other difference is the brand. The Trail Cruiser had an Atwood and the Mountaineer has a Suburban brand. The water is scalding hot in the beginning, so I don't think the thermostat setting is too low. I don't dry camp, so the camper is always hooked to fresh water. I am using the same water pressure regulator as before. The electric element is turned on for washing dishes, but the gas is also turned on app. 30 min. before taking a shower. Other than the shower head being less conservative with the water, I don't have a clue. Does anyone have this problem or any suggestions?
Thanks