You will find a blank map in this thread. Make a snip of it and apply the plots in paint yourself. I already have the data of multiple runs towing my trailer in 5th and 6th to show that I get better fuel economy in 5th. So does my brother doing the same windy and hilly 160 mile commute to the coast that I tow mine in. And soon my father in law might, but he has a different engine and the terrain he will be towing is much flatter with less wind.
Your calculation are based on only towing on flat terrain which is not the case. It is also very windy half way through the 160 mile drive. So windy in fact that you pass through a giant wind farm for about 30-50 miles. And I already posted where I will be at with different grades and speeds earlier. My grade is more likely to change over my speed which is generally 65 mph or 70 mph on rare occasions.
