GRU-JFK flight in Jan 2023 on 77W (one way). Paid $2071 for biz. First was being sold for $6321 at time of booking. After ticketing, app offering $1200 to move up. While tempted, there are 2 of us so that is $1200 to move up from a J to F lie flat seat with some more amenities, though the majority of the 9.5 hour trip will be spent sleeping. Plus we're already booked in the mini 2 row J cabin which will be cozy as it is.