In Europe the names are different. We have rated range, which presents the highest range number. Then we have typical, which is close to the EPA rating (this is called Ideal in the US i think?
Rated and typical are the ranges projected on the dash behind the steeringwheel if you choose range as indicator for SOC.
Rated and typical (ideal) are based on fixed consumptions. They might be adjusted through sw-updates, but not dynamically.
I.e. I get about the same numbers when driving like a madman for a period in winter (-10 degrees celcius) as I do in periods with very sparse consumption in 25+ celcius. If the numbers were in any way affected by the driver, they would vary greatly.
However - the Energy app on the big screen projects range based on real consumption. You can switch between 10/25/50km average and instant/average consumption to project range. In addition, the trip planner gives quite good estimates for remaining SOC at destination.
So there`s no doubt the car can show range based on your driving habbits. And range based on model (60D has different consumption as base for the rated/ideal (typical) than a P90D). But the numbers are not dynamical. I`ve driven 2 Model S` for three years, following Tesla and forums closely since 2012......
And then - topic:
When I received the car brand new in March it showed 574/459 (rated/ideal) km.After about 7500km/4 months it showed 455tkm (deal). So less than 1% drop first 4 months/7500km.
In conclusion - my 90D does not suffer from the initial serious drop in range.