Gas meter Volume conversion faktor

On my gas meter there is noted ft³. In my bill is noted a volume conversion factor of 2,83. According to my using and the calculation of kWh by my own it looks like that the volume conversion factor is wrong, it should be 1.

Can you help me?

If the meter reads cu ft, then the conversion factor is 2·83 to bring it to cu metres.
Multiplying the cu m by 11·15 will give a pretty close estimate of the kWh, plus or minus a bit depending on the calorific value.