Have been shooting my .308 at 600 yards, using mil dots for the needed hold over. Decided to zero at 600 yards, and it turns out that my Vortex would not allow that many clicks. So I bought a set of the Burris Signature rings with the inserts, plus the .020 inserts for the rear ring. This puts me at 20 MOA at 100 yards. To sight it in, I will start at 100 yards, where I should be about 13.5" high (depending upon load). This means I would need to need to down click every up click I have put in, and then even more. Does this sound right?