I own two of the units. 1 on my .308 and 1 on my .22 mag. I installed both of them 3/4" forward of my stock. The .308 groups went from 3/4" @ 100 to 1/2" at 100 yds. The .22 mag groups went from 1/4" @ 50 yds to same hole @ 50 yds. I paid $16.00 for each of them. I feel that is an inexpensive improvement to my guns. I have had them for several years and have experienced the improvement. This is experience versus theory.
Mmmm. Not saying you haven't experienced a change, but 1/4" may also be attributed to a 20* change in ambient temp, or a 5 mph(or less) difference in crosswind.
If its consistent, hey, get on wit your bad self.