New 2015 Ram 1500 ECODIESEL HFE

I have a 2009 cc ram box with hemi with 252,000 miles on clock and tow 33 ft TT. 7200 lbs on scales. On a good day I'm 8 mpg.on a stiff windy day 6 mpg. I use my truck for work . Do 40-45,000 miles a yr.
I'm going to look at the eco diesel. Max towing is 9400 lbs .Max mpg is 28-30
I've done the math when disel was 4.50 a gallon and gas was 3.75 a gallon. In 2 yrs it will pay for it self.