It can boost average in some situations.When you score runs, your average goes up. When you get out, your average goes down. If not outs were boosting averages, a 0 not out would see your average rise. But it doesnt.
Have another look at those numbers now that you know that they are averages. His NOs were not changing his average. But they were lowering his expected average in relation to having the opportunity to bat the innings to completion.
Some one batting at 9th position can score 4* - 15 times , but not sure if we can argue that batsman should be seen as regular 60 avg top order batsman. Volume of runs is also important.