Cannonball,
Yes, I agree that you need to shoot the gun. I believe the Spot on is a good starting point. I set up a 167 yrd shot to mimick what Spot on told me per the dot. I hit a couple inches high. Could have been me though. I also tried the 217 dot and at that range I was dead on height, but a little to the left. Probably me on that one. The bottom dot for my set up is 344 yards. I didnt try that one as I wouldn't on an animal. When using that one, the hold over was pretty extreme when looking at the main crosshair. Again, I believe it is just a good starting point. Zeroing in the gun with your own chart would be the best formula.