Here's a crazy thought.
Tesla went from 85-->90, 3k IIRC. 70-->75, 3k too... so we all got used to a $3k or so battery upgrade uption.
Now:
60-->75; 8.5-9k.
So, let's just say
90-->105; 9k?
Maybe marketing is trying to get us used to a larger price point for a larger battery upgrade? Testing the waters with 60?
Here's to hoping that those newer 90s out there are limited 100 or 105s...
I think I read somewhere that someone asked Tesla how much it'd cost to change out the 85 battery for the 90, and the price he was quoted was on the order of 22k. Elon has been quoted as saying that present Model S owners should probably wait until a more significant bump in battery capacity before upgrading.
90 to 105 being 9k doesn't sound unreasonable, but with an ever growing Supercharger network covering most long distance travel needs, is there really any additional benefit to keep raising the battery capacity? You're just dragging along more weight. I'm guessing they're going to take a look at the numbers of people upgrading from 60 to 75, and see how that compares to the numbers of people purchasing 90s.
When I was first looking at the Model S and deciding between the 60 and the 85, the Supercharger network wasn't as built out as it is now. These days I'd just recommend to people that they get the 60, and get the 60D if they need AWD.
Compare to costs of the upgrades:
60: 210 miles range / 75: 249 miles -- 39 miles for 9k ($231 per mile/$600 per kWh).
60D: 218 miles range / 75D: 259 miles -- 41 miles for 9k ($220 per mile / $600 per kWh).
I'm extrapolating for the 90D ($89,500) vs 60D ($71,000) -- cost for the additional range is $18,500
90D: 294 miles range -- 76 miles range for $18,500 ($243 per mile / $617 per kWh)
P90D: 270 miles range -- 52 miles range for $18,500 ($356 per mile / $617 per kWh)
If there was a 90 to 105 upgrade, it probably would cost 9-10k -- you'd probably get another 38 miles on the 105D, and 26 additional miles on the P105D.
I'd argue that the 60/60D range is good enough for most people -- the 90D is really only when you do a lot of road trips/driving where superchargers / EV charging stations aren't as commonplace/available.