I've looked at the difference between CAL asymmetry calibration made on the ground with cosmic muons and on orbit with using CNO.
Difference between ground calibration and on-orbit calibration made in August 2008 is show on the plot below separately for each of 10 segments along a crystal. Each histogram entry represents difference in asymmetry calibration constants for one crystal, converted to equivalent position bias in mm, using average asymmetry slope( 0.0022 per mm).
Each histogram shows gaussian spread with RMS ~2.5 mm, but the first and the last segment have also substantial systematic bias ~4 mm: 