What's up with these new rotors?

30 plus years working on big rigs was always told, taught, and trained to use a matched set.

There is no such thing as a new matched set. That's a myth. It's just like piston rings wearing into a cylinder. THey aren't matched until they run together......and even then with wheel bearings, It's just not that critical. I've seen people swap sides with bearings for years with no trouble.

But everybody does it different.