The particular example with PG was the last time I looked at this site and its obviously inaccurate. I didn't search up an example to discredit that site. I am sure this type of data is difficult to collect.
So what is your problem with Lance on defense? Until GH was injured, he and Lance shared the traditional PG duties. I really don't care how much he played one position or another and to be honest (even if there accurate) I don't see much value in these stats( especially considering the limited minutes and other variables that are ignored). This isn't a one on one game and not scoring says nothing about defense.