There is an error in the win percentage calculation.
The SEC calculation is taking the 13 ties as half wins giving 6.5 wins while the ACC calculation appears to be taking the 5 ties as full wins giving 5 wins for their ties.
The adjusted calculation for the ACC gives a win percentage of (143+(5/2))/276 = 0.527174
However the SEC calculation is rounded funny. The actual SEC calculation is (184+(13/2))/361 = 0.527701
Prior to this season, the corrected calculations actual gives the SEC a .0005 advantage.
Where did www.ncaa.org get their numbers? I think it's like everything else. Everyone always hates the king of the mountain. Finally, if you calculate using the ties as full wins like the ACC was calculated above:
ACC (143+5)/276 = 0.536232
SEC (184+13)/361 = 0.545706
This gives the SEC nearly a 1% advantage prior to this season.
Check the math before you post. You may see that the calculations are fudged slightly to give the SEC a disadvantage. This happens. Look at ESPN's commentating. That is skewed against the SEC every week.