Just checked the fact sheet in the link, very interesting data. I had a hunch that this was the case, as I had shared it here back in early December (quoted). I also the think the true number of showcase invites are somewhere between the numbers you both have mentioned (neither 250 or 468 per se). Conservatively, I would probably guess the true number probably lies somewhere between 280 to 320, which is somewhat close enough to the 10% they put on their showcase website. Considering acceptance to matriculation ratio (which I think ~2:1 is a decent guesstimate), I think everyone who got a showcase invite has a decent (conservatively ~35-45%) chance of getting in either at the end of initial round of acceptances or later from the waitlist.
On another point, based off of previous years' threads , I think they're currently meeting on Wednesdays and determine who gets accepted, waitlisted and who will be rejected.