However it was used during certification flights and of course the evacuation testing done in hamburg. Actually evacuation trials were done after 71 seconds (iirc) and therefore they can increase pax load considerably in larger versions if airbus ever builds them, talk about a 1000 pax airplane.
79 seconds.
But this does not matter. Even if a manufacturer should demonstrate by testing that they can evacuate all passengers in 10 seconds, it is still not allowed to have more than 110 seats per exit pair. Airbus 380-800 has 8 exit pairs, so the seat count cannot be stretched past 880 unless exits are added. The evacuated configuration was 538 on lower deck, 315 on upper deck, so that if A380 is stretched, it shall need two extra exit pairs - for both decks. I do not quite see where the sixth main deck door would go. B747-800 has the same issue: as the -400 can have 539 main deck seats, a stretch would raise a need for sixth door pair.