Thirsty little Fiesta

[oatis]

Not sure if anyone here has the same problem. My CL 5dr Auto is so thirsty that I never get near 400km per tank (it usually runs up to about 360km). This is almost like I am driving a family wagon. This is just city driving running on ULP or occasionally E10. I regularly check my tyres so that's out of the equation. Is this normal?

Can anyone suggest if Ford would be able to fix this? I'm not sure there's something they can do to the ECU or Catalytic converter to improve the situation. I haven't had the oil change since new so not sure if that helps either.