Let's for a moment go along with the situation that a wrong figure was set up in the box and not picked up (for this incident or others that happened).
What can lead to such errors?
1. Some guys state this should have been picked up by "feeling" the speeds can't be right for such a weight. With the optimizing on computers for many different flap/weight/reduced-thrust settings, this becomes very difficult. With former aircraft it was simple: Less flaps -> higher speeds. Today, and especially with Airbus, this simple equation no longer applies. How many times was I surprised when changing the figures (LMC),by what kind of weird different speeds resulted.
Solution: Maybe a more linear and logic function would help us.
2. Second reason is overload and overcrowding of the cockpit during preparation, leading to serious distraction. It is a utterly silly EK characteristic, that the augmenting crew (2 in this incident) have NO seats allocated to them in the cabin. They are doomed to go to the torpedo tube (lie down only!!), situated in the very remote back of the aircraft when airborne. For the whole ground time and TO/Ldg, however they will be confined to sit in your back. Now having the loadmaster, mechanic, purser, company representative already trying to bring in their priorities, the poor two sods only block space and bring in distraction. As much as I like 4 more eyes during T/O, Ldg or emergencies (which is NOT possible inflight with the crap EK set up!! because they are stuck in the back!!), as much do I like a calm cockpit during preparation and all kinds of calculations, so as to NOT screw up these things.
Solution: Maybe EK should go over their management induced bad set-up.
3. Time for preparation is another factor. As EK does not provide its crew with company laptops, nor provides them as a standard with internet access (home or abroad), this leads to receiving the figures, notams, WX etc. and access to charts upon arrival on the aircraft only. We all know that the stress only starts then. A thorough preparation going through all that stuff might be easily disturbed by too many sods hanging around. Sending the flight info to the hotel would allow studying during transport, as the really cheap variant, but not even this is done by EK.
There is a lot of room for improvement there, but, halas, it all costs some Dirhams and they are unfortunately spent on more VPs, but not on operational improvements.