I have never hunted for antelope, but 2 years ago I had a perfect shot at what would have been the biggest mule deer of my life... He "ducked the string" and I shot over his back...
The dilemma you face is that the animals do not always jump, or duck. I've had animals stand perfectly still, and then the next one jumps or ducks...
My rule of thumb is that anything over 30 yards, the animal will move enough to dodge death... but you can't anticipate it. Can you imagine if you adjusted for a jump, then that buck just stood there as the arrow flew over his shoulder..?
Aim true and you will kill more than trying to adjust for jump or duck...