Alignment to target and group location on paper...

I had an outstanding practice session on Monday. I went back to the range yesterday and put up a slow and timed fire target hanging on different target holders. I shot my slow fire group in which I was in perfect alignment to and my group was centered. I got lazy, and stayed put and adjusted my NPA for the timed fire target. I shot my 10 shots and felt great about the string...come to find out my group was out the right by about 1 inch. Could the alignment to the target cause this zero shift? I am asking because I watched one of the better shooters at my club moving his table every time he shifted firing points.

Yes, I believe it will affect POI.
Long time bullseye shooter - if my grouping seems to be off by an inch or less, I will sometimes shift my left foot forward or back a couple inches rather than start "chasing my sights".
For me personally, this would be more prevalent in timed or rapid.

I base the position of my body and stance off of the comfort level I feel in my neck and head while looking at the target. I shoot at a range for practice where the targets are not always lined up from 50 to 25. I have to shift when changing from slow fire to sustained fire practice. 

I start off by getting into position/stance and then looking to the target. If it doesn't feel right I may shift inward or outward depending on the direction of strain I feel in my shoulders, and neck. A final check will be to do the same and add in the raising of the gun to see how I'm coming down. Am I too far left? Am I too far right? Adjust accordingly. 

Now for how all this relates to my slow fire shots, I notice that the longer I hold onto a shot, the shot will gravitate towards the direction I need to back off of and that's IF I feel my grip and trigger control was performed the way I need to in order to put the shot where I'd like it go. Obviously if the shot didn't go where I'd like it to there could be other mistakes being made. 

For sustained fire I will notice that again, as I fatigue, shots drift toward the direction I need to back off of. 

Just how I work.

Sometimes its a grip and not a stance/position issue.

Your group can shift from re-gripping alone.

Jack H wrote:Your group can shift from re-gripping alone.

And artificial light vs natural or cloudy vs bright day or sun over your left shoulder or right shoulder.