Using their formula:
In the first 15,000 mile driven this year I have used 956. 874 gallons of fuel.
I WISH I had paid their theoretical $1. 35/gallon (my average for the year is $1. 65).
Anyway, using their methodology and my driving style and a few thousand mile of towing, my cost would have been $1291. 78. Well below the gassers.