.. and, if one doesn't land by shortly after the 1000ft markers, then one is eating into the 1.67 AFM pad ... eat too much and too leisurely and one might get egg on face syndrome if the runway is getting towards being landing distance critical.
As to using actual, rather than AFM, data on the line .. utter madness in this certification engineer's/pilot's view .. just asking for a screw up sooner or later. If it's good enough to use factored data for planning, then it's good enough to use that on the line other than in an emergency situation. Dinosaur ? .. you bet.