You are obviously an APS convert.
What I have learnt since I first read the Deakin articles about 15 year ago:
1) APS don't know as much as they think they know.
2) Engine manufacturers know a lot more than APS give them credit for.
In a disagreement between the engine manufacturers and APS I give the benefit of the doubt to engine manufacturers.
What causes detonation? How about:
1) Heat
2) Time
Detonation is definitely associated with insulator cracking, but APS do have a tendency to put anything that doesn't fit their narrative down to LAMEs dropping plugs or manufacturing defects.