Could it be that the combination of very high levels of oil (24% *is* high) and slobberingly rich running (meaning that a *lot* of oil was present) in the first runs caused very little wear -- but also did very little to run the engine in.

Maybe the leaner runs produced the wear patterns you've noticed as a normal part of the running-in process.

Remember that running in involves the wearing of parts so that they achieve satisfactory operating clearances so to do this *some* wear must occur.

Maybe people will be a little less worried about the effects of a rich-run with their ABC -- that's fine (if they're using 24% oil with a fairly high castor content) -- otherwise we can't tell.