Before I contact Leupold on this, I'm betting that there's some Ifishers with some experience here. Weapon: 300 Win Mag shooting 180 Nos w/ Reloader 22, 75.5 gr. The ammo has stayed constant throughout this process. With a VXII 3 x 9 (not AO model), I got about 1.5" high at 100 yd, even at 200, -2" at 300. Switch to a VXI 4 x 12 and I get 1.5" at 100, -2 at 200 and about -9 at 300!! To make the question as simple as possible, could the scope change cause that much error? Again, everything else, except maybe temperature and air conditions were the same.