Can somebody explain the difference between...

[[Za...]]

I'm measuring a recess depth on a part:
And I want to know why the results differ so much when switching from "Center" to "Maximum".

Also, our customer is verifying the parts using PC DMIS (which I know nothing about), he says they use the "average" method. Would the "average" method be the same as "center" on Calypso?

Thanks in advance,

Zach

[[SH...]]

It all depends upon on the form errors of the two planes and parallelism between the two planes.
If form error and parallelism approaches zero, then your variation also approaches zero.