Yeah the two crew independently coming up with the exact same wrong figure, having made two completely different types of mistake, and that figure that they wrongly comes up with is a reasonable figure, and then both having the same misinterpretation of the Vref40 rule..........
I think the above scenario would make winning lotto look easy from a probability perspective.
"Hey Archie what weight did you use?" is much more likely. Happens all the time.
We'll handled by the crew by the looks of.