Yeah the technical writer is using common core math..........You know where you have to subtract to add and 2+2 takes 4 steps to get to 4...
CPU lanes and SLI arent the same though. Any card made in the last several years needs a minimum of X8 to even work. No matter what you do you cant do more than 3 on a 28 Lane CPU, thats in all the board manuals.
In this table is shows a 28 lane CPU supporting 32 lanes.
With a 44 lane all is good and you can run X16, X8, X8, X8 if you want. Sadly Nvidia does not support more than 2 since pascal hit the scene. I read up on this one a lot and a several reviewers tried it and actually got worse scores adding a 3rd card. If you are using them for nose mining....uhh I mean BC mining tou can probable get better results but that doesn't involve SLI AFAIK. If you could get any tangible benefit out of it Id be all over it. For what I've spent already whats another $1600 on two more Strix 1080 Ti OC cards.
When Im ready to switch over to the RVIE rig being my main Ill plug in the two Strix 1080 A8G cards to see what happens. My bet is what I have will deault backwards to the 1080 and Ill end up with worse performance.
Out of my RVIE user guide 1-8 The dual config on the 28 lane is impossible and it would be X16, X8 amd even the single would be X16, X8, X4

“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein