Usually each year in late December Starwood adjusts the categories that each hotel is in, determining the new number of points required for a property’s award redemption in the coming year.
This year, since they’re introducing a new more expensive “category 7” for redemptions on February 1, they’re delaying the usual category adjustments until that time as well. Now, that doesn’t mean in practice that every hotel will be adjusted on February 1 — some usually happen a few days before the changeover, some a few days after (since in this past it’s been a cumbersome process for the programmers). And occasionally hotels get changed during the year as well, usually based on a review of their revenue that they request Starwood Preferred Guest to undertake.
So don’t take this absolutely to the bank, and still do make your speculative bookings now (since most hotels will go up in points required, and reservations are generally cancellable but check the cancellation rules). But it looks like we have an extra month to redeem at the old, lower points prices.