I suspect that you are getting a little more velocity out of the KIK than Goex...The ball leaves the barrel faster so there is less time for recoil to kick the shot high, so the ball goes lower...

The largest grizzly bear registered in the NMLRA record book was killed with a .54 ball and 120gr FF Goex...The shot was taken at 100 yards and the ball passed through the lungs and lodged under the hide on the off side, the bear went less than 50 yards after the shot....

That .58 ball will do it's job, you just do yours...