why crews from one or two UK airlines call " maintaining FL XXX " when they reach their assigned level, have already been radar identified and no change of frequency has taken place?
Perhaps it is because they have requested a higher level and it is just a polite 'hint' to give the controller a 'nudge' that you are waiting for further climb. I know that I've done it in the past. Controllers have been known to 'forget' about you from time to time.
Agree that there is no need to 'announce' your arrival at a FL whilst under radar control just for the sake of it though.