Except that the other data is certainly suspect. I mean - what other source of realistic data can they possibly have that is realistic enough and large enough

Except that the other data is certainly suspect. I mean - what other source of realistic data can they possibly have that is realistic enough and large enough to be more significant that 100000000 miles of actual usage? At this level, it's the odd, unpredictable events that are going to get you, and whatever models they have cannot include all of those.