On Saturday, October 7, 2017 at 4:36:45 PM UTC-7, wrote:
If that airliner goes over us in level flight at 9000 instead of 6000, it isn't consuming any more
volume. It does possibly eliminate one descent step for the approach controller which is likely
why they do it.
UH

What Steve was trying to say is that if the plane were to be flying a steady descent from 9 to 6 it would be consuming ALL the airspace from 9 to 6, not just the diagonal vector. So they cannot vector a plane at 7k across that path because it's *possible* that the plane will descend from 9 to 6 in less than a mile vs. the hoped for gentle descent.

5Z