I believe the article, but there are still more factors in gas mileage than they mentioned.
For example, I have a 5-speed, and my trips are 1.9 city miles (my daily commute to/from work). And I get around 25-26mpg. Marty (basilisk4) who lives 30 miles away from me (same climate) has an automatic (higher EPA ratings on mileage), longer commute, and still gets crappy 21-22mpg. Both of us can be considered leadfoots.