OP back with an update, since a thread like this is useless without one.

I held the step an extra three weeks instead of stepping back down, and it settled. Same dose, same everything, just more time — which is exactly what was suggested upthread.

KevinCompounds said:

The useful move here is to separate what is established from what is widely repeated.

Coming at KevinCompounds’s question from a different direction. The mechanism and the magnitude are separate questions. Agreeing that something happens says nothing about whether it happens enough to act on.

Adding the numbers, since they settle part of this. For anyone reading later: the numbers in this thread are worth checking against a primary source before you act on them, including mine. Half the figures circulating in this community trace back to a secondary summary that dropped a qualifier.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

One thing that is still open after KevinCompounds’s answer:

What would you measure differently if you were starting again?

Dr.PathRoch said:

For anyone reading later: the numbers in this thread are worth checking against a primary source before you act on them, including mine.

Careful with the causal language. Two things moving together in a period when five things changed is not a mechanism, and stating it as one makes the thread less useful to somebody reading it later.