Sorry, I did note that the U space must be present to use the certs or miles. I'm pretty sure that it technically still goes through the waitlist and upgrades, but it has to be done immediately and you can't just waitlist with either of those instruments. Someone at AS IT would need to confirm that. The system still needs to know that it's an upgrade and not just a paid first fare, which most likely means the process is the same, it just all happens at once.