Hi Alex, thanks for your question...and its a good one!
The first thing I would say is that you absolutely cannot compare results of a 74 test and an 80 test and assume that they are the same board.
We have rarely found 2 boards in a range that work exactly the same and even when we do, the role of 2 different sizes is quite different. For instance, different wind conditions, sail sizes etc
So I think the simple answer is that the tests cannot be compared.
I am 100% confident in the results that we found within that test, as we spent a great deal of time on the boards in a good range of conditions. The only conditions we didn't get to test in were proper, powered down the line conditions. I believe that Surf Mag do most of their testing around Cape Town where its very rare to get cross on sailing, so perhaps this could also explain some differences in what they found?
Anyway, if you are thinking of buying one, there are some mega deals going on them at the moment (I saw some new ones going for £700 a week or so ago - for whatever reason that might be?!), but I suggest you try it first to make sure its suits your sailing.
Good luck!