Speed I think probably makes a difference, but not so convinced by the people in the car. Usually TFL tests in Colorado. I'm not sure if the elevation would come into play at all.I watched the video. I can tell you 2 things that took the mileage just below 40.
1) 75 miles per hour on the highway test. I believe the EPA does 65MPH. That would make a HUGE difference as most cars mileage really starts dropping off after 65MPH
2) Two people in the car. Does the EPA test put two people in the car? the extra 160lbs or so would affect mileage
as for the difference in mileage between pump and civic computer, its because the GPS speed and computer speed were off by 2MPH. This is most likely due to TIRE size issues since its determined by wheel spin.