Steve,
Just some information on configuration.
In Config >General Logic your rotary should be configured as angular.
The motor tuning units are steps per degrees for an angular rotary axis.
NOTE:
Ignore the linear check boxes.
The checkbox for linear/angular only tells an axis not to convert when switching from mm to inch, other than that it has no purpose.
A, B and C are always rotary axis and the DRO shows in terms of degrees.
Example for calculating motor tuning:
For my rotary using micro stepping and a 72 gear ratio:
200 steps / rev X 1 rev /360 degrees = .5555 steps / deg X 10 micro steps X 72 gear ratio=400 steps per unit
RICH