If you use the comparison tool on Tesla.com it shows the S and X as (est.) range number. Y or 3 show (EPA est.) aka sticker range. My guess Tesla has not yet finalized the range testing. I would not be too surprised to see the EPA estimate to be higher than what is listed today.
Could there be a possibility that the range has increased, but they are now reflecting a closer 'actual' range? They've been brow beat a lot by some reviewers, since some other EV's are getting much closer to, or better than EPA.
I believe by law they have to report the range they achieve on the EPA test as part of the Monroney sticker for the car.. But, I agree, the EPA figures are rarely achieved in real life. And are not all that useful unless people start driving 60 mph down the highway (fat chance).