though I agree the POH is the legally binding doc.
Are you 101% sure about this?
Calling Creampuff????
The POH is a story book with lots of examples on how you could operate the machine, on how certain things work and perform.
If one was to take that statement too literally, does it mean as the airframe ages and it now stalls 1 knot differently it must be grounded?
People seem to forget that the FAA when certifying the plane only cared about section 2: LIMITATIONS.
I have a feeling over the years, the notion of legally binding in all areas has started as folklore and is now law.
As an example, two identical airframes, same part numbers on the wings and flaps etc, can have two different statements on "short field" take off.
I may be wrong, ready for a nice serving of salted crow, but I think most folk have accepted folklore to be law. Myself included.