Is there something shady going on with CPS transportation policies?

Last year, my son was admitted to a classical school near downtown but he was unable to attend because their busing policy does not officially extend to our neighborhood on the South Side. That said, I had noticed a bus for the classical school outside of our neighborhood school in the morning. When I asked the Principal about this, she gave me the runaround. The CPSOAE office eventually gave me a barely satisfactory explanation that students within the transportation boundary had moved mid-year and were permitted to keep their stop outside of the boundary. This year, there is supposedly a bus for a north side academic center in our neighborhood but that school's policy is also officially limited to the 6 mile limit. It seems like there is an off-the-books transportation process that I have been unable to access.

Does anyone know about this? Is there an incentive for schools to declare a 6-mile limit even if they practice something different? As far as I know, Whitney Young is the only academic center that openly claims to bus students from all corners of the city.