Being a chat, I think this sentence can be understood in two very different ways.
a) "Once we reach the waitlist closure at T-48, most of the waitlisted upgrades have been confimed."
b) "Very few waitlisted upgrades are confirmed before T-48 and the majority of clearing is done at the last sweep, T-48"

My take from the webinar was the tweaked process would mean interpretation a. They way they spoke it sounded like they usually had none or very few left on waitlist after the final run. And that they would start earlier and process the list more often, and thus clear more pax off of waitlist at earlier opportunity. I have a hard time believe this until I see it in reality *) but that is what they said.

The meaning in b) is more in line with how it has been. And of course agent can be speaking from their own experience from the past. And then it says very little about what you can expect.


*) I have decided to put the tweaked process to the test. 2 longhaul segments have been added to the waitlist around 130 days out. I think that is decently early and should be slightly ahead of the pack (just a guess, but I don't think very many ticket purchases and upgrade requests are made more than 6 months out)
Request is from economy extra to business and that might slightly increase chances. Being gold and being 2 pax on the reservation means I have the chances of a snowflake in hell, in my humble opinion. But I am at least trying the "improved" waitlist handling before making conclusions.