AFAIK, there has been no change to the AIP...
What has crept in more is "assigned FL130 left FL230"; really confusing if you clip it, or someone else is talking to me on a non VHF line. Would prefer "left FL230" only; otherwise I'm obliged to confirm the level you read to me when vacating, which might lead me (and does) to say "say again assigned level"... But we've already been there and done that when I originally gave you the level...