Wanting to move it back one rail slot due to a tweak in my config.  I won't have a chance to zero it before dusk/night of my next hog hunt.  

What I'll likely do is keep it in its current slot as I know it's zero'ed, but in theory, moving the DBAL back one slot should lower the POI and POA, correct?  For 100y I'd suspect just one click down would re-zero it, right?

ETA - or it one slot so minute I would;t even move the laser at all?

Your guess is as good as any.

It will be close, but you may have to tweak it.  Too many variables to know for sure.

Let me remove guesswork to allow for feedback:

distance - 100y
angle - the barrel and rail are at a slight angle upwards at that distance
ammo - shouldn't matter but m193

With that 2nd fact above, would;t any move from either the optic or laser backwards bring POA and POI down a bit?

FPNI (even with your updates)

It depends on how well the rail is aligned with the bore axis. If the rail is aligned with the bore axis, moving the laser backwards one slot shouldn't change POI, but you can't be sure until you test it.

Rib you still have the T1 on the rifle, right? Just re-zero to that.