Me thinks "Who cares?", since you are already up, even in the most precarious situation from a performance point of view (i.e. engine-out), you are expected at least not to descend any further; and that "old saying" is pretty much of the single-engine pilots, because for them those little meters you just left behind could prove to be of life and death.
Just my 2 cents. Not to offend you, nor anybody else
No offence taken. For the SE guys (Or even some smaller ME), you're entirely correct. Point is, that in larger ME aircraft, performance is calculated, and provided that you calaculate correctly (EK Tailstrike comes to mind), it doesn't much matter where on the runway you start from so long as you've calculated from that point - generally speaking of course.