I have now owned my Mitsubishi Outlander PHEV hybrid 6 months and refuelled it 4 times. It was advertised as having petrol economy of 1.9L/100km. Over nearly 10,000km I am averaging 1.7L/100km.
My refill today averaged 1.0L/100km. I'm finding the 50km pure EV range to be fairly accurate but that does drop if I drive up long hills or use A/C. I've been economical but not super careful this time. Many return trips from the city are finished using fuel to supplement the depleted battery. I've been driving with A/C on as it gets warmer, generally if it's over 25 degrees celcius or I'm making calls and need the windows closed.
A side benefit is control over refill timing to take best advantage of the fuel price cycle. If I miss the best price even with one third of a tank, a two week wait for the next low point is no problem or concern.