You guys have to keep in mind that the guy wasn't 100% hard when measuring. When we measure, we make sure it is absolutely 100% hard as it can get when we measure it. And we make sure the ruler is right at the skin exit point. He was being measured by someone else, standing up with a boner. I imagine if he had stimulated himself and measured himself, there would be an additional 0.5"-1" of length.
Any of us measured the way he was being measured would fall short of what we measure ourselves at.