As it appears to be unmanned transport's mission in life to prove RR's triple spool engines, and apparently also the A380, an inferior product I would bring somewhat more than a pinch of salt when digesting any of his posts.
Anyhow, as the MLW and MZFW delta across all the weight variants of the A380 is between 20 and 25 tonnes and it is not possible to dump fuel from the engine feed tanks (which have a combined capacity of around 91 tonnes) it does not take a slide rule to figure out that the purpose of the jettison system is not to bring the weight down to MLW or below.