Hi Barry.....welcome to the Club
Firstly, most fuel mileage claims by manufacturers are vastly outlandish and have been proven to be fixed.
A few years ago pretty much all the major vehicle manufacturers were caught with their pants down when it came to true mileage claims from a tank of fuel.
However, when it comes to the most recent vehicles then there is now a transparency with claimed mileage and economy.
Two things that are inherent with Hybrids is that you are constantly carrying the weight of the batteries no matter how full or empty they are the weight will not change, unlike a tank of fuel.
Also, the Hybrid does need to regenerate so constant freeway driving for example would not lead to topping the batteries unlike driving around town.
Maybe it is worth trying different roads with more bends and stop junctions at a moderate speed to see what difference it makes to the range.
Let us know what you find