I did JFK-FCO, was a last minute buy and I didn't do the online bid for an upgrade, but there were tons of seats in the business seat map. I went early to the airport and inquired about any upgrade and they processed it for $610, which looked to be cheaper than what the minimum bid options online were for that flight. They did write "no lounge" on the ticket.

On the return I did the online bidding at the minimum as it looked empty, and the upgrade cleared around 70 hours out. A bug in their online tool wouldn't let me pick a seat if I'd already had a seat selected on the first flight - I had to "delete" my saved seat for the first flight (??), and then it would allow me to pick a seat for the upcoming flight. Lounge access was automatic for this, and the FCO lounge was worth it, very good food, pizza in particular, wow.