But then, are the statistics about "points per 100 possesions" flawed?
Yes. I had a quite nice shooting guard at C in a patient, defended man to man by a quite good center with very low ID. He was expected to get 96.6 points per 100 shots. After three quarters, he was 0-11 (0-2). The number of my games I've seen guys have 90+ pp100 and shoot 20 or less percent from the field and from three is probably in the double digits, if I went back through and documented them all. Of course, it occasionally goes the other way too - against the team that drafted him, the same player once was slated for a 93.3 PP100 and went 18-33 (9-17).