awblain... Yes that does make sense to me too, however, i have also had it explained that without brake fans, there is very little flow between discs, and that is why using the heat-synch of the whole brake unit can be more effective.
I have operated A330 without fans, and after engineering advice, found brakes do cool more quickly whilst still applied. Hard to prove I know, but curious to hear anyone else's experience.
Skyjob... that is also a great theory, however our hands are not made of carbon/metal, and so there is little heat absorption inwards.
Cough... I know the limitations well, but have also read guidance that 150-200 deg is best at commencement of takeoff, for maximum braking efficiency. And that is what AB may have used in certification.
I am no specialist on the subject, so happy to learn from anyone wiser in these matters!