Grace Quirrel,
Hopefully our errant off thread ramblings are not too distracting ...
Slasher,
A bit confused here without having in front of me the particular docs to which you refer... is the 6000/4730, which represents around a 25% penalty, from the manual/QRH for the same conditions ?
My concern with your post is that, if the QRH refers to unfactored distances, then one ought to interpret that to mean something along the lines of "in the conditions specified, and you're otherwise having a good day, if you do everything right, don't float, use maximum effort braking, and are reasonably lucky .. then you might go close to achieving the QRH distance .. but don't stake your life on it".
Subject to what the present QRH says (and mine might well be a revision or two out of date), and how it relates to the AFM, I would be very surprised indeed if Boeing is suggesting at all that the QRH figures bear any resemblance to what the line pilot will achieve in a routine landing.... That is why the certification factor of 1.67 is there in the first place .. to provide some fat for the normal variability we see in the landing manoeuvre. When you consider how the performance model is developed and, more importantly, validated by flight test, then one ought to be very cautious when the manufacturer makes reference to unfactored distances ...
If you are able to do so, I would dearly love to see a scan of the two sets of data as that would make it much easier for me to get my head around how you are viewing the situation.
.. and the beer is a foregone conclusion ...