Barr,
You should still be centered, (right & left) at 50 & 100 if you are centered at 25 yards. But just aim low- I wouldn't aim BENEATH the deer- make sure you have brown in your sights, but I would aim at the lower 1/3rd of the deer's body out to 100 yards. If you want to shoot past that, you really need to go out to the range one more time and re-sight in the gun. Good luck hunting!