Discouraged by ICAO unless there is traffic. See Doc 8168. If you research the historical versions, you'll see that the paragraph saying "do not mandate it for each and every level-off" has grown to 2 pages long explanation.
The latest Eurocontrol ACAS bulletins since about No. 13 started to deliberaltely misinterpret ICAO on this, Eurocontrol not to be trusted. KPI hunts and professionalism often do not mix.