One other thing to consider about upgrading on the CO n/s EWR-HNL flights: it's pretty unlikely that you'll be able to get an upgrade unless you're going at a very non-peak travel time, as the 767 which CO uses on this route has only four rows of BF seats (20 total, less 1 reserved for pilot rest). As the upgrade fee is non-refundable (at least your miles are refundable), it's a gamble, and not a very good one. I fly this r/t several times a year, and have begun simply paying the BF fare rather than coach + miles + upgrade fees, which comes out (if you buy enough in advance to get a Z fare) to be about the same. I have never been on this flight when it's not sold out (at least not since they stopped flying it with a DC-10; yes, I've been doing it for a while).