The chart seems to be hit and miss. I have several balls on the current list that do not seem to be correct while others are. Examples of incorrect ones are Columbia 300 Freeze actually covers more boards than the Track 715A for me, even with both drilled for length. Not to mention that my Storm Natural seems to out hook both of them. Of course, that might be a surface property.
Given that the chart can only show the three dimensions, I can't say how it could be improved though.