You are correct, the PM does not have the right to notify this event.
CE notifications are dealt with under clauses 61.1 (PM) and 61.3 (Contractor), the significant change in quantity event at clause 60.4 is for the Contractor to notify.
CE notifications are dealt with under clauses 61.1 (PM) and 61.3 (Contractor), the significant change in quantity event at clause 60.4 is for the Contractor to notify.