The issue is that the EPA has a new testing methodology for plug-in vehicles, and Travis Parman, director of corporate communications for Nissan of the Americas, said, "this new EPA testing methodology means this is not an apples-to-apples comparison."
What it all boils down to is that the 2013 Leaf has two charging modes: the default "100-percent Long Distance Mode" that maximizes range and an optional "80-percent Long Life Mode" that Nissan says will optimize long-term battery health. The EPA test, which is being used for the first time on the 2013 Leaf, blends these two modes. Previously, EPA range estimates were always based on 100-percent charges, whether the cars had another charging mode or not.
If the old EPA test (i.e., 100-percent charge) had been used on the 2013 Leaf, Parman said, the result would have been 84 miles. The increase is due to, "refinements made to the MY13 Leaf's regenerative braking system, reduction in vehicle weight and enhanced aerodynamics," Parman wrote. The EPA's estimated, non-blended range estimate for an 80-percent charge is 66 miles. Parman said official EPA numbers should arrive in early March.
Aside from the efficiency changes, the 2013 Leaf was updated in other ways, with Leaf owner help. A light in the charging port, a locking port cover and smaller headrests are just three examples. Oh, and the car is now $6,400 cheaper, too.