This was written in response to jan Telakoman's adaptation of the CEFR fluency system for Toki Pona.
There's something I'd add to this, at least as a foot note in the B1-B2 area if not a meaningful part of a specific category:
The value of asking questions to gauge and/or correct your understanding is significantly higher in Toki Pona than in natural languages, where the jargon is an effective anchor of your understanding.
Skilled speakers aren't just skilled at expression and comprehension; they also are quick to ask appropriate questions when they don't understand something. Not understanding a statement has stopped being a hindrance or a reason to switch to another language; you can correct your understanding and continue in Toki Pona alone.