Truthfully most knockouts are nerve attacks as loss of consciousness is due to disruption of nervous system function. Some people for whatever reason can absorb much greater shock to the exterior before it translates to a knockout. The severe beatings taken by Mike Tyson and George Chuvalo come to mind. We're talking repeated heavy hits from heavyweight boxers flush, yet didn't fall. But then you look at Roy Jones, not to say he is glass jawed, but a single hit on the chin in the second round from light heavyweight Antonio Tarver laid him out.
In regards to Dillman, there is a film clip on bullshido.com that exposes that art. One of his former students tries to KO a news woman with a pressure point strike and she yells something like, "That hurt, you hit my ear.", then no knockout. The only people he could drop with his pressure point strikes are his own students.