JEP AU-806
3.5 CHANGE OF LEVELS
3.5.1.6 The pilot-in-command of an aircraft, receiving an instruction from ATC to change level, must report:
a. when the aircraft has left a level at which level flight has been conducted in the course of climb, cruise or descent; and
b. when the aircraft leaves a level for which ATC has requested a report.
JEP AU-902
1.2 SUMMARY OF REPORT AND BROADCAST REQUIREMENTS
1.2.1.4 After any ATS directed frequency change, pilots must advise the last assigned level and, if not maintaining the assigned level, the level maintaining or last vacated level; e.g. “MELBOURNE CENTER (CALL SIGN) CLEARED FLIGHT LEVEL TWO ONE ZERO, LEAVING FLIGHT LEVEL TWO NINER ZERO”.
NOTE: The “last vacated level” may be omitted by identified aircraft squawking pressure altitude derived level information.