he is right. tune tune tune.ELKhuntR said:
also many guys dont think about it much but there can be slight differences different angles. arrows do goofy things when compared to flat shooting (standing on the ground shooting a bag across your yard) or straight down shooting. i put a telephone pole on the edge of an old bridge span and practice straight down because many of our shots are down in deep DEEP ravines and you need to know how they will shoot like that too. maybe i just had some goofy heads but mine had to be tuned a little further for those shots. didnt change the flat ground poi.