This is inaccurate. The Insight Internal Combustion Engine always runs to propel the car. The Electric Motor is only used to provide additional boost when needed such as accelerating and climbing hills. The Electric Motor also is of course used to regenerate power when the battery management equipment deems it necessary.when the gas engine is in use it burns gas and lowers the mpg. When the electric motor is running it does not burn gass.
As a side note, the mileage per gallon of gasoline you are getting is great! It is more difficult to drive for best mileage with an "automatic transmission" which the CVT is basically. The reason is that automatic transmissions are simply less efficient than manual.
2000 5 Spd