PBL
It seems to me that the flap track damage (not the "major damage" as the manufacturer put it) lies outside of even the 15° region. Since all damage is supposed to be covered by the assumptions, this led to my wondering if the acceptable-means-of-compliance guidance would be revisited.
Fair point, however the divergence angles were derived from statistical data and never considered absolute. Neither is the protection of the aircraft considered absolute. Taken in total the rule is aimed overall at "best practices" that should maintain the fleets within a broadband of historical acceptability.
There probably is some room to find improvement here, but I suspect it will have to be subjectively aimed at the certifying angency since they often decide what trades they will ultimately accept.