I can't assist much with academic part of the question. I am quite sure our performance calcs assume 455 m flare (increased from 305 m years ago). It's probably written in the ReadMe for our third party performance app.
These days I am not so interested in what the book says anymore. The reality involves glide slopes of varying quality, glide slope PAPI mismatches, non-standard runway markings, short- and slippery runways. The PAPI and G/S enhances the visual references for judging your path and obstacle clearance. When visual references can be establised in other ways it's an eyeballing exercise. No need to land longer than necessary. All in my opinion, of course.