I don't keep shooting if two aren't close. Why bother? I pull the remaining loads apart. Just extra wear and tear.
I think this is what its all about. Like I said, I just read it and interpreted it the way I saw it - the idea of using two shots as a start.
I think the idea was to start testing with two shots, and like Fireball said if they are not close then move on.
I did this last night. I started load development with some new Hornady bullets in my 7-08. I had already found a load with Sierra bullets, so I knew kind of where to start. I loaded some up and shot them into a decent group. I did shoot 3 times - just couldnt help myself.
Then, I decided instead of playing with powder charge, I would play with OAL. I started with .020" off so I shortened it up to .015" off. The first shot was way high and left. Honestly, I thought to myself I should stop there and seat the other bullets deeper, but I just wondered if it was one of those magical fliers. So I shot another.
That one hit low and left. At that point this whole conversation made sense to me. I did not even bother shooting the third and went back to the shop to seat it deeper.
On the other hand, if/when I do shoot two in tight together it just makes sense to shoot another one in there to see what happens. And I suppose, if that 3rd flies in there close it makes sense to send another one in to see what happens. So on and so forth.
But I am almost next to positive the original thought that I read was for those loads that don't get anywhere close to each other with the first two shots. Relatively speaking of course. I suppose you would have to have a base line to say what close vs far away is.