I actually find the US site a lot more realistic. In three different vehicles, we've never obtained the Cdn numbers, but have generally been pretty close to the US numbers. I believe they revised their testing methods a couple of years ago to better estimate real world driving. Of course YMMV. heh
US site has L/100km too. Not sure why people still use MPG in Canada when gas is sold in litres and cars' tripometers are in km :???: Seems like unnecessary work.
Did you use US gallons or imperial gallons when you did the math? Now that you mention it and I looked into the mileage for my F150 and my old 4runner I was never able to obtain as good mileage either. Only the Jeep seems to get the same mileage they advertise…works for me!