I have GUI that controls the N9320B via GPIB. My GUI allows the user to select between Center/Span and Start/Stop freq and the display on the SpecA should reflect the users choice. This worked on the now obsolete Agilent SpecA that has been replaced by the KeySight N9320B. The KeySight display changes between Center/Span and Start/Stop when the front-panel buttons are used but whatever mode it is in when my GUI is launched persists through the entire session irrespective of what SCPI commands are sent.
If anyone has overcome this "feature" or has a valid experiment I would love to hear about it.