After my first miss, when I went home, I shot a broadhead at a target in my yard at the same range and it was right on.
After the second miss, I carried the same target out to the woods on a Sunday and fired from my stand to the approximate spot where the deer was. It was a couple inches high, but that could have been a minor error on my part.
In either case, I'm open to the idea that I just screwed up, but I'm also considering the noisy xbow and dodging deer theory.
I'm taking my son hunting sometimes, and I sure hope he has better luck than I do if he gets a shot...