I may be wrong or even weird when it comes to this subject.
I think our brain and eye work in ways that many don't understand.
As our muscles have memory so does our eye and brain, me thinks.
One of the reason good groups can be shot under the above stated it that whether it is realized or not, the image at the first shot is memorized and used or the next several shots.
This works for those miracle groups that don't happen all that often as usually atmospheric changes between shots occur.
I shoot 1/2 MOA groups at 200 yds regularly when the target dot is totally covered by the scope. When the target dot is increased in size to be able to quarter it the groups drop significantly (when the wind ain't gusty).