Does either switching between G20/G21 and/or parameter #115 (where it exists) cause the unit display to change from three to four decimal places for Inch use?

I looked through the parameter list in the manuals for both versions and couldn't find anything remotely looking like a scale factor. Earlier entries in the Parameter List imply such things as pulses per MM for distance. If it is assumed that the G code selects Inch or Metric for display purposes my guess would be that changing the Parameters (#34, 35, 36) to 640*25.4 = 16256 or whatever your leadscrew to motor gearing gives you, would solve the problem for Inch users. Perhaps the data entry in the manual should be Pulses per unit of distance travelled, rather than Pulses per MM. I can't remember a CNC system where changing from G20 to G21 did anything other than move a decimal point in tool or work offsets. It did however cause scaling for axis moves.

By implication all this suggests that the DDCSV varieties do not have a switchable Inch Metric system - but it can be set up to work with the right pulse counts for either Inch or Metric, but not both without changing parameters. The loss of Parameter #115 may indicate the system is simpler than expected. Do people still switch between the two systems?

My two penn'orth