Whoh hang on John your preachin to the converted mate! If you go over my last post again youll see Im a staunch advocate of distances derived from the AFM, and the QRH distances as a back-up only to AFM distances (Ex: AFM says I legaly required 6000 ft of runway on the day, QRH says Ill probabley use about 4730 ft of it in landing and stoppin the damn thing). In my last post I meant what distance of runway Boeing expects me to use (actualy chew-up) on the day, not what primary method of distance-derivation Boeing expects me to use. I meant it in that interpretation.
However I think youve answered my original question anyway.
After all that I think its time for a beer!