I would be somewhat leery of locking in an itinerary that forces you to take JL 48 ("forces," in the sense that if you had to break this into two separate flights you'd be over the 21 segment limit). Every time I've looked into this flight (or the GRU-NRT direct JL flight in the other direction), I've seen D0 and A0. Maybe that's a glitch or something, or maybe people have been able to get seats, but I was sufficiently nervous about it, that I ended up finding a different routing.