Just from the dates I've been looking at... The pricing for Premium Economy is sometimes $3000+. Yes, I know, demand and the timing is excellent. I've done the route 3 times, and love staying at a nearby hotel when I have a 6-12 hour layover.
I'd love to go to Tokyo again, but can't at those prices. Cheaper for me to fly to any nearby location (HKG/ICN/TPE) and then book a separate ticket.