You should check your tiller. You can force any bow's nocking point higher or lower, by adjusting tiller. Whether it's high or low, isn't extremely important. It will affect the nock travel, so a bit of testing will tell you where the bow tunes best. Most bows and cams are designed to be shot with the arrow close to perpendicular to the string. I've found that experimentation with tiller to be worthwhile when dealing with many single cams. Since different draw lengths can affect cam position, you may get better nock travel at some draw lengths with tiller that isn't even.

In addition, some like adjusting tiller to get a particular feel to their grip. Moving tiller can make the grip naturally hold higher or lower.