I will say owning a Z5 that I find those numbers questionable if it scores 87 and is joint second best smartphone camera on their chart.
I really like the Z5 and it has a decent camera but it's no way as good or better than a number of those devices which I have owned that score lower.
With that in mind, I don't really trust their findings tbh, so I'll stick with actually using them and discovering which takes better shots for me.
I think there could be a few devices on their list that shouldn't be as high as they have them, and likewise things like the iPhone 6S Plus takes in normal use better photos than my Motorola X Force (droid turbo 2) which is still very decent, but shouldn't IMHO get same score as the 6S Plus based on my own usage and taking lots of snaps with them.
Samsung however, undoubtedly make some of the best flagship cameras and deserve to be in top positions, but some of the others sailing around the top - leave me questioning them and their methodology.