The spread at the muzzles isn't the only thing that can effect regulation. The barrels can be squeezed together at any point by your wires and wedges which will also effect regulation. So if you have more pressure on one wedge than before, you'll now be shooting wider. Not as much pressure as before, now you're shooting closer or crossing. You may get lucky and have no change. Worst case scenario you are going to be starting over again with it very close.