Years ago it was said that shooting finger style the top should be 1/8" to 1/4" less brace height on the top limb compared to the bottom and wiith a release, even tiller. I have found that sometimes a slight adjustment in tiller must be made if your limbs are not matched perfectly. I would try small adjustments on the top limb to see if your grouping tightens. A good reference is on how far your nock set is above centerline with a bow square.