That part is outdated. Every node will get a minimum number of audits as soon as it stores at least 1 piece. Let’s take an extrem example. It will take a bit longer to vett 100 nodes over vetting 1 node but it will not take 100 times as long. Vetting these 100 nodes one by one will take 100 times as long so you can as well start them all at once.
I would also clarify that. The group of unvetted nodes gets 5% of all uploads. The group of vetted nodes gets 95% of the uploads. If both groups would be equal in size that would mean a node gets 19 times more uploads as soon as it gets vetted. Now the problem is these groups are not the same size. If we have 19 times more vetted nodes then unvetted nodes you would get exactly the same traffic. If we have even more vetted nodes you might get less traffic as soon as you are vetted.
Download traffic more or less depends on the used space. An old storage node holding 5 TB will get 5 times more download traffic then a storage node holding 1 TB. Vetted nodes will not get more download traffic just because they are vetted. They need to collect used space first. This statement is also a bit too simple to always be correct. I would say over all a new node will start with a slightly lower number of repair downloads. The repair traffic should slowly increase over time. → The download traffic will differ a bit from node to node. The point is vetting has impact on upload, uploads will be followed by downloads, getting vetted doesn’t change the download selection.