I believe there were cases people talking about situation at different times for different individuals instead of "pure" number across the board.
The general consensus seems pointing to recommendation of more content review when it is around 7 to 8 and below. But that is referring to "consistent" pattern and not a single or short term performance in either FL or diagnostics.
At the same time, there were cases when people get "stuck" at a number say 10 or 11 or even 12; and they wise to get higher. In this case, the conversation seems wrapping around "I need more content review".🙄