I ended up canceling a few hours ago so as to not risk messing up an upgrade for someone else (shouldn't work that way, but...) so I can't report back with any certainty. However, I suspect I would have easily scored the upgrade at some point prior to departure, and you're correct that this flight appears to stay open in J for longer than other frequencies on this route. I think you've got a fighting chance, just don't expect anything prior to a battleground upgrade :/