Or..... If you are doing partial fill-ups with only a small amount of fuel each time, it is pretty hard to fill back up to the exact spot each time giving you skewed results.+1 Your calculations will be more correct if you run through more of your tank between fill-ups.
I haven't added any gas yet but I did just switch to reserve coming to work after 200 miles.
40-44 for me.About the same for me.