Availability is getting quite limited for certain types of tickets. If of interest to anyone who has not purchased yet, today I am seeing (for example):
18 seats for Weekend Packages
15 lower-bowl seats for Session 6, Championship Pairs Free Skate (Groups 2&3) & Championship Women Free Skate (Groups 2&3)
[For upper-bowl seats, plenty of availability.]
(I have not checked every ticketing category. Just trying to give a general idea that it's possible that certain types of tickets could sell out by the time that January rolls around.)