I conducted another experiment this weekend.
Driving 70 miles each way at 55MPH while pulling a 4800lb RV and 8 passengers in my Expedition I was getting 7.6 mpg. Before I left the campground to come home I added 3oz of acetone to the 10 gallons of gas I had left in the tank and drove to Kroger once and then hooked up the trailer for the return trip. For the trip home, it was about 15 degrees colder on the trip home, so that would cause a slightly richer fule mixture (meaning that if it were the same temperature, the "with acetone" mileage would be slightly higher) but I was still able to get 10.7 mpg on the way home. That was an increase of 40.78%.
I was totally blown away! No pictures of the dashboard, but what reason do I have to make it up.
My friend has been adding 2oz to every 10 gallons on his 2008 GMC 4 door pickup and his combined hwy/city average has gone up to 18.9 mpg, that's about 24% increase. He is going to try 3oz per 10 gallons, and I will give an update after his testing. I will also try to get him to do a hwy test at 55 and 70MPH.