There are four things that can radically affect your actual range:
- temperature
- speed
- terrain
- the nut behind the wheel
There's others, but much less (usually), and that's proper maintenance, mostly tire pressure and load.
If a person is conservative, minimizes use of the HVAC system, accelerates and limits top speed, the range can dramatically be higher than someone that either doesn't care, or is not paying attention. It's a personal tolerance thing on what you are willing to allow to attain maximum range. Community average as indicated by the app is 4.1m/Kw. Given that, and on the 2014 a usable capacity (not the full capacity since the computer won't let you use it all to help maintain the life) is around 19Kw, so 19*4.1=77.9. The documentation implies about a 10-20% increase by moving to Eco mode, and about the same amount to Eco Pro. Some people use those modes, some don't, and if you are careful, you can approximate those enforced restrictions even in Comfort mode, but you have to watch what you're doing more closely - the computer does it better. It's harder to maintain that average in the winter than in the summer unless (probably, since I don't live there) maybe someplace like Yuma, AZ, where it gets so hot for so long. It's hard (and maybe unhealthy) to limit your a/c use, so that can take a fair hit on your range along with the battery's need to cool itself if pushed.