It is only the movement of the tone arm that will tell you this pc is assising charge and unburdening his case.
(If true it would make it easy for a totalitarian government to stop processing )
Something of a generalisation, especially as I have taken out of context
I have certainly used more than the Tone Arm in observing the pc's progress.
But I have ended process on other very good indicators. Phone sessions and some objectives seem to work that way. From about '54 to about '57 meters where not used. (I think this is remarked on in <I>Dianetics '55<D>)
But then I am not working with the sort of processes mentioned here, or with pcs with heavy attention on past (perhaps famous, or Scientology) lives or on so called OT levels.