The chart is not official, it's just more accurate than the previous one. And since Tesh made the chart out of memory of others' opinions and with what is more or less general consensus when their hasn't been discussion over it, it's not going to be overly accurate. If character discussions can get underway, and we get opinions from other character boards and deep, informative opinions from the Sonics, the chart will become more accurate and factual to an extent.
And because of differing playstyles and the like, the chart will never be 100% agreed on anyway. I have bias toward DK myself, and consider that matchup even to slight disadvantage, and the Falcon matchup even, but I think Sonic can slightly beat Mario, and loses hard to Peach and Wolf as well.