The number of perfect CR+M is over 2,000 for Class of 2015 according to CB which is a lot greater than the number of 2400s. I would bet that is what the schools are referring to, as the writing has never been quite considered in the same way.
I thought the point of the Amici was to show that other factors are being considered by schools than simply SAT scores and grades. That is, while Fisher may argue that her stats are better than some other kids being admitted, the amici are saying that they do not automatically admit all the perfect candidates and may well admit a kid with lesser stats over a 4.0/1600 student due to other factors.
Is there any data on how well kids admitted to UT with lower SAT scores do in comparison to the kids from well-off suburban high schools? Is there any difference?