Why would a 100D be the same price as a 90D? I expect at least $10K more.
If Tesla stuck with their recent pricing, it should be around $6k more - 15 kWh jumps have been 9-10k for the last year or two.
Decoupling Supercharging will presumably allow a price drop, and Tesla also needs a chance to reset pricing downwards to reflect cheaper packs and prepare for the 3 - I'm pretty sure they can't afford to have S and X sales stop when the first 3s are being produced, so they need some combination of pricing and technology/features that keeps it interesting in the face of the 3.
I am expecting to see a bunch of new tech/feature additions to the S/X in the next six months, but I'm also expecting to see some moderate price cuts. Of course, I could be wrong...