This sounds like the good old 'over ride height' or 'on blocks' confusion...
We are currently running CX's indoors on carpet at our club and I am running 5mm front, 4mm rear droop measured on blocks. But as always it depends on the amount of grip you have.
Chris Grainger talks about it around the 8/9minute mark in the video below;
http://www.youtube.com/watch?v=J-StH...layer_embedded