Idunno
A very clear explanation of the practical (as opposed to exam) use of BFL, with one small inaccuracy - the BFL figures in the manual do not give the MAX performance, just a simplified one that is fairly close to max. If you apply your template to a particular runway and it is not long enough, you may be able to "make it fit" by doing a full performance analysis taking into account stopway, clearway etc. Obviously if the runway is a Balanced Field (exam definition), then there will be no benefit.
The penalty for this simplification is exactly as has been described - you ignore all the runway beyond the "template" which could be used for stopping after an engine failure or accelerating to an increased V2 for obstacle clearance. But if your operation is one where you are rarely "performancearily challenged"
, then this is a penalty that many companies are happy to take in the pursuit of simplicity = less chance of silly cock-ups!
Happy Flying
BJJ