personally I would make big cuts at the central office and redistribute to the schools

Amen.

  That number jumps to 65.4% for kids with college-educated parents, and 81.3% for grad school.

Do you think those kids are learning primarily due to their experience at school, or because their parents teach them? Anecdotally, whenever I've walked past Kumon centers during the weekend they seem busy, and when I was driving the other day I noticed Russian School of Math has added a new location.