Jepp 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 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
How is this interpreted? Only report when asked to? Or in both cases?