historically, the additional weight of automatic transmissions and efficiency losses through clutches resulted in automatics getting less fuel economy than manual transmissions. the crossfire with autostick weighs just 24 or so lbs more than the 6-spd and it has a lockup torque converter that eliminates the losses experienced through the clutches while at cruising speed. the autostick transmission programming should result in more efficient shift points than the average 6-spd driver which explains the higher fuel efficiency ratings of the auto. Then again it might have more to do with how the EPA tests the vehicles. Anyone ever look at the test profiles? Who drives up to 56 mph in the city, but never exceeds 60 on the highway?
http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

i would guess that there would be a minimal increase in mpg by accelerating conservatively in "W" or 2nd.