Not necessary here
In the US it is not necessary to report leaving or reaching an altitude unless requested by ATC. Indeed, such reports are discouraged by controllers. I believe that the only exception is when an aircraft is issued a discretion descent.
I don't see the logic in ICAO's reasoning on this. Must lead to a lot of frequency congestion in busy sectors with aircraft transmitting all those reports of leaving and reaching altitudes.
I toured Moscow Control several years ago, and several controllers there were annoyed by US pilots not making those altitude reports. Clearly those pilots should follow the flight regs of the country they are flying in, but I still thought it was humorous because over here we get annoyed by European pilots giving altitude reports.