In the link below you can see the differences between the old EPA ratings vs. the new ratings for the Disco II...Seems much more accurate.
http://www.fueleconomy.gov/feg/calculatorSelectEngine.jsp?year=2002&make=Land%20Rover&model=Discovery%20Series%20II
http://www.fueleconomy.gov/feg/calculatorSelectEngine.jsp?year=2002&make=Land%20Rover&model=Discovery%20Series%20II