> """Elsewhere, Facebook admitted to exaggerating the number of full views that video ads received"""
You can tell they didn't do any homework, since the issue was that full views were under reported when the audio and video tracks were not the exact same length. The result is that full views were actually roughly 35% greater than what page managers saw reported.
http://newsroom.fb.com/news/2016/11/an-update-on-metrics-and... goes into the details of what the issues with each metric calculation is. You can draw your own conclusions as to whether each was (a) important and (b) favored FB. That link also goes into FB's plans for next steps in making metrics externally audited and more transparent.