Dr.SurgeonPGH said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

Adding the part of the answer the thread has not reached. If two explanations both fit, the useful question is which one predicts something the other does not. That is answerable; arguing about which sounds more plausible is not.

The figures, for anyone assembling their own picture. 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.

One thing that is still open after Dr.SurgeonPGH’s answer:

Did your prescriber agree with that reading, and if not what was their objection?

lucas_SP_BR said:

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

I do not accept the framing. The question has been narrowed to the version that has a tidy answer, and the part that was dropped is the part the OP actually asked about.

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

Closing the loop. The answer turned out to depend on the detail I had left out of the opening post, which is a lesson about how to ask rather than about the subject.