Which of the following statements about processing cycle efficiency (PCE) is not true? 6 6 It is a measure of operating process efficiency. It is defined as the ratio of processing t time to non-processing time. It is based on the relationship between actual processing time and total production time. The optimum value of PCE is 1.0 It incorporates notions of value-added" and 'non-value-added," as discussed in the development of activity-based cost (ABC) systems