I dunno, my experience differs. It seems to me that prices go down a bit when the public onsale happens -- because there are more tickets going into the system -- and then as people realize they don't have a line on tickets at face value or near that i.e. they check with friends or whatnot, typically prices then begin to rise. I would expect them to peak in this situation once we know who the opponent is... example, I think if it's Arizona again, prices will drop, if it's Detroit, they'll probably go up a bit (novelty), and the pricing now probably anticipates Carolina so not much change in that case. Prices will start to drop about three days before the game as there are a lot of people who won't let spare tickets sit around much past then and will drop the pricing to get them to move.
FWIW the Divisional tickets are much cheaper on Ticket Exchange and StubHub this year than last year at the same time...
