A completion is defined in HCO Pol Ltr 30th September, 1965 as certified or classed or graded. It is further defined in HCO Pol Ltr 17th October, 1966 Issue II as Grade Rehab, S & D, assist or Sec Check.
Since each question of a Triple Grade is considered as a type of process by itself which handles not a different Grade (process subject matter) but a different flow (aspect) of the subject being addressed, for statistic purposes each flow of a Triple Grade should be considered as one PC completion.