Including known failures does not provide a valid trend as a whole. Garbage in, garbage out.If you exclude data, it's no longer a universal average.
But don't let that cloud your thinking.
Besides, if you want to really get picky, all UOA universal averages are garbage by your metrics, because the simple fact that because it costs roughly the same as the oil change, the data set eliminates all the people who refuse to spend extra and simply “check the box” on maintenance. They likely neglect their engines to a degree which is not likely matched by those who perform UOAs. So you’re never going to get a “universal” number anyways…