There are several factors that can cause variations in the point of impact.
Verify the screws that connect the riser mount to the riser are tightened to the maximum torque specification of 6.7 N-m (60 lbf-in) and the mount is securely attached to the bow.
NOTE:Do not exceed the bow manufacturer's recommended torque values.
Verify each adjustment knob lock screw on the mount is tightened to the maximum torque specification of 2.2 N-m (20 lbf-in).
Verify you are using the correct arrow profile for the type of arrow in use.
Range your shots consistently at full draw or at rest.
Inspect your bow and confirm all of its components are in good working condition.
Always use consistent form when shooting a bow. Variations in stance, grip pressure, and peep sight placement can affect accuracy.