RE: sighted in... a mistake???
Each gun and each load is different, and the only way to know for sure is to shoot at those ranges and find out. Sighting in at one distance, then shooting a game animal at another based on assumptions is a good way to make a less-than-lethal hit on a game animal.
I listened to somebody that told me where to sight in at 25 yards to shoot 250, and long story short, I educated a coyote (at 100 yards, mind you) because of it. In my rifle, that had me shooting 5.5" high at 100.[:@]