I believe the numbers for the model year 08 to 10 NAH were converted by formula to the new method, but it seems for 2011, they're requiring the full 5-cycle test for some cars.
, take a look at the links to http://www.epa.gov/fueleconomy/420f06009.htm
and search for 2011.
From the 07, 08, 2010 and 2011 data files at http://www.fueleconomy.gov/feg/download.shtml
, I looked up the NAH and the unadjusted (unadj) city, highway and combined numbers are the same:
46.8 46.6 46.7098
However, in the 2011 file, I notice extra columns and these numbers:
City 5-Cycle Unrd Adj - Conventional Fuel
Hwy 5-Cycle Unrd Adj - Conventional Fuel
Comb 5-Cycle Unrd Adj - Conventional Fuel
33.0977 33.2992 33.1881