Shy Torque and spinwing:
You are both absolutely right about the requirement for fuel flow information. There is no requirement to have range or endurance information in the flight manual (it's not required by the certification standards, and would not be 'approved').
But we hang people who run out fuel on cross-country flights. Why the authorities don't require it as a minimum is beyond me. Maybe the insurance companies ought to start demanding it as part of the fit....
Put a fuel flow device in your helicopter, marry it up with your GPS and learn how to use both, and you'll be a lot better off.