Even knowing sight height and ammo and atmospheric parameters exactly, running them through Sierra's Infinity, I've never been able to get the sight-in at 20-something yards trick to work. I'm on the paper at 100 but always a couple inches off, pick a direction. Just as easy to forget the complications and bore sight, shoot one at 25, adjust, another at 50, adjust, then finish up at 100.
I won't argue that. Again, I said essentially the same thing earlier in the thread. If you look at the plot, you can see that small changes in sight height yield fairly large changes in zero. Its not trivial to determine this to a 1/10". It is best to know how your gun shoots at real-world distances.
