There are so many reasons.

First, there are more folks who own the Camry and therefor more folks exaggerating their MPG. I'm not saying they are lying, but I believe that anyone getting over 40 MPG, in ether car, is doing so with serious hyper-techniques that most folks don't or can't do. The Camry is NOT a Prius and anyone claiming better MPG then the Prius is not driving normally.

Second, the NAH is only sold in the Northeast where is is bitter cold and has terrible traffic or California where it gets very hot and also has horrible traffic. Where are all the results from southern or mid-west drivers where traffic is more normal and driving conditions are much better? They are driving Camrys.

Third, the ICE is different but this is not a bad point on the NAH. Many folks believe Nissan's 2.5 engine compares very well fuel wise to the standard Camry. The NAH uses the same engine but as far as I know it HAS been retuned to the Atkinson cycle. This is why it only has 158 horsepower while the regular 2.5 has 175. That combined with the 40 HP electric motor gives the NAH it's biggest advantage over the Camry, 198 HP with almost no difference in MPG in federal testing.

Finally, the Camry does have the ECO button which the NAH does not have. I am still not sure what this does, but from what I gather it cuts power to the AC/Heat and only cycles them very low. The NAH has built-in cycling but is probably a compromise. I have been told that the Camry's MPG is not that great at all without the ECO button on.

If you get over 34 MPG, you are doing fine, but I can't wait for spring to come back.