If you are keeping proper form there should be no major differences in your where you are aiming and where you are hitting. If you just move your arm downward towards the animal, you are moving your anchor resulting in your shot being off. Try bending at the waist to keep T in your form and if you do it correctly you should hit where you are aiming. Now if you are trying to shoot EXTREME angles, then it could be the angle coming into the equation. A normal set up 15-20 ft up in a tree and not shooting into a 20ft drop off and you shouldn't have a lot of problems if your form is correct.