As with my old Insight, the "real world" figures blow the EPA numbers out of the water. When I was so inclined, I could get my economy down into the mid 2s to mid 3s. Since this car uses pretty much the same system, I'm guessing you'll see some pretty impressive economy numbers...if you aren't driving the car like you've stolen it...
This is nothing like the Insights system, except that they both have an IMA.
Hybrids boost MPG in three ways:
1: Recovery of wasted braking energy (regen).
2: Keeping the Gas engine in the most efficient range by running on EV power alone, or aiding the Gas engine.
3: Having a very efficient gas engine you wouldn't normally include (Atkinson, undersized engine with lean burn).
Of these the most important thing is #3. Have a very efficient engine.
In the this case all three MPG boosting effects are weakened.
1: CR-Z Regen energy recovery is compromised for brake feel.
2: CR-Z has no EV only mode as it is in other Honda hybrids (weak but at least they have one).
3: The CR-Z engine is not a special economy motor, it isn't a small 3 cyl, it isn't Atkinson, it isn't lean burn. It is just a standard Fit engine.
All in all you would expect a small bump on Fit mpg and that is what you are seeing.