Hey Beepbeep - WELCOME BACK!
Great insight, as usual.
That explains why I can run my engine in higher AFRs than may be considered safe, and no issue.
There is a limit of course, but I seem to be inside that. The engine certainly likes to be in the 12s (low end). So that would suggest the setting of the boost dump Pierburg switch is more important than we may think. By delaying the dump too much we risk issues in the lower rpms rather than the top end AFR. I just do my best to avoid being in the 10s anywhere.
Regards
Alan