The difference between 100 and 150 for zero, might be 1/2" impact at 100, with a .30/06. With irons, it's a moot point. Could be that's where the sights happened to hit with the factory filing job with the ammo they tested it with. What they used, probably isn't the same ammo you are likely to be using, anyway. You are going to have to shoot it with the ammo you can buy and see for yourself. Maybe it is actually zero'd while the 150yard sight, at a mere 50 yards but the leaves are zero'd at 200 and 400? I might not even be shooting any where near the sights - you must shoot it for yourself. Usually, the '06 shoots higher with higher speed ammo, but not always- depends on the how the gun is set up for drop and fit as well as how you hold it.

For example, IIRC, I had my 9.3x57's rear sight set (filed) for about 2" elevation at 100 with the 2,300fps 270gr. Speer bullets. The shot on the moose at 200, hit right on the bead, right where I expected it to. Perfect. With a flat shooting rifle like an '06, I cannot see having separate 100 and 200 or 150 and 200 leafs, unless perhaps you are shooting nothing buy light loads with a 220gr. bullet - but even then - moot.