I am not going to put much faith on that test. First, both lenses need to be taken at the same focal length. Second, they should use a full frame so corner sharpness can be determined
they have tested at the same focal lengths. of course they included the 105mm too.
you have to watch and understand the review video.
if you read the website, they are working on a FF review.
Who legitimately tests an L series lens on a cropped sensor anyways...?
photozone for example.. and i did not hear complains about it.... http://www.photozone.de/canon-eos
i think they may had a bad sample. but that gives me not much faith either.
as roger mentioned the 70mm end showed quite a lot of variation.