Tesla shipped the 40 kWh Model S with a 60 kWh pack and then software limited it to 40 kWh. Once this was revealed, 40 kWh owners could pay Tesla to make a software adjustment and give them access to the 60 kWh pack that was in the car. Fast forward... Many are speculating the Model X will come with a 10x kWh pack (let's say 105 kWh), and that when that happens Tesla will simultaneously offer this same 105 kWh pack with the Model S. Of course many people with orders for Model S in will want to shift to this pack. Could be a real PR and logistics nightmare for Tesla as orders are changed/cancelled, or perhaps shifted to Model X. However... ...what if for awhile now Tesla has been shipping 105 kWh packs with the 85s and software limiting them to 85 kWh? When Model X is revealed and design studio offers a 105 kWh option for the Model X and S, they can also offer to the last few thousand VIN numbers that they can upgrade for a fee. We've been expecting chemistry improvements these last 3 years, current 85s could weigh about the same with a higher efficiency battery. Of course if you were a VIN right before that special number you'd have a gripe, but a much smaller one than if you'd ordered a couple days before the announcement. I'm not sure I'd handicap this a probable, but would definitely score it as possible.