Using Dmetric:

In the old 10-volume description, we see that the sensitive material volumes near z~0 are not centered at z=0:

Shifting the old description's sensitive volumes by +25 cm, and then showing the difference of 25 cm shift minus unshifted, we see that this does not change the size of these volumes:


With the new 1-volume description, and then showing the difference of using the 10-volume minus 1-volume, we see that the 1-volume description creates the more-expected distribution of material in z:


-Gene