Your figures definantly seem high for a car with such low kms and subtle driving habits. I know the auto definantly does go through more fuel (I have compared them). I have an '05 Luxury; 97,000kms; Fuel Average Hybrid 8-9L/100Kms (City and Some HWY), and filled up with 50 litres (bit before fuel light) and have already got around 410 kms and needle is still just above half. I drive conservatively, very rarely go past 4,000rpm. I use BP Ultimate.
For such high figures I would be looking at a few things. If your keen to do some simple DIY testing, it would be wise to look at things that may affect your fuel ratio but not enough to trigger an ECU Trouble Code.
Get yourself a can of electrical Contact Cleaner.
- Clean MAP Sensor (Located on the front of the Intake Manifold)
- Inspect Oxy Sensors (Professionally Test them)
- Inspect Air Filter Element
- Get your ECU read at Honda or reputable mechanic if you haven't already.
I would be looking at a possible faulty/contaminated MAP/MAF sensor first and go from there.
Also Inspect your spark plugs and report back the colour.
White: Lean, High Temperatures (Incorrect Plugs(need a colder plug)/Lean AFM)
Grey/Light Brown: Stoich (Running Well most likely)
Dark Brown/Black: Rich (Rich AFM Issue)
Black/Soot/Fouled: Running Very Rich or Burning Oil.
If you live in Melbourne, I'm more than happy to help out.
Remember: The key to fuel efficiency, the majority of time is how you drive. Shift at optimal points (difficult in an auto though) (mine are around 3-3.5k usable torque starts at around 2600rpm) and low throttle. High RPM or Anything over one quarter to a half throttle will unnecessarily use more fuel.

