I have ~70,000 miles on two P85's, both have settled in at ~260 miles a full charge, but I agree with Zbane - there are way too many factors that effect full charge, speed, weather, pre-conditioning, heat, cold, tire pressure, headwinds, weigh in the car, bike rack, rim size, tire brand, rain, software update of the week etc.
The car constantly tries to gauge your driving style and frankly a 6 mile difference doesn't mean anything - too many people get hung up on it on these forums - drive the car and enjoy it.
If I bought today I would get the 90D it sets the new standard for the new technology and the 85's will be viewed as a less premium model vs the 90. (think Mercedes E320 vs E350). If a 100D came out tomorrow I would buy that instead etc... $3500 is good insurance if you get into an extended range challenge. I think you made a good choice - early in my ownership experience I would have paid $10K more for 50 miles of range when i got caught in a blizzard with my family and could have used the extra mileage to reduce the pucker factor. I quickly learned the limits and planned accordingly. Both cars are awesome - so don't get me wrong it really comes down to your lifestyle and where you live realize some people only need a 60... Also no one drives 55 - when you are doing 80 into a headwind you are only going to get about 220 miles of range anyway...