In my opinion, there is an error in the calculation (made by MMC):
The amount of CO2/100 km comes from the burned fuel per 100 km.
In the current specification a combined fuel consumption according to the NEDC of 7.1l/100km is given.
7.1 l petrol results in 169 g CO2.
Where should the "missing" amount of CO2 come from? From the driver?