To anyone doubting the validity of this scenario: Stop doubting.
One of my former employers introduced a staff review ("and development" - yeah right) scheme some years back, with gradings 1 (excellent) to 5 (not so good). As a sweetener, staff getting consistently excellent reviews would get accelerated payscale increments, bonuses, etc. But this was in no way the introduction of performance-related pay, oh no, HR were very clear on that. Oh, but if your score wasn't so great you might not get your next pay increment.
Unfortunately for HR, this was in a world-leading University, where the big cheeses always went on about how that excellence was all thanks to the excellent staff, many of whom were world-leading experts in their fields.
So, not surprisingly, lots of the first year reviews came back as "excellent". Obviously. Staff at a top-rated University are specifically recruited for their excellence.
Next year, HR "reviewed" the scheme and sent out guidance to departments about what (small) percentage of staff were "expected" to be rated as excellent, along with a not-very-veiled threat that departments that got it wrong would have all ratings reviewed to produce the expected stats.
So Heads of Departments had to explicitly down-rate many review ratings to fit HR's imagination of the distribution of excellence or otherwise within an "excellent" institution.
It seems improbable to me that a company would have a formal policy which actually requires such ratings. Policies are usually open to employee review, and always discoverable in litigation.
No, far more likely that a non-critical manager's reviews would vaguely suggest that he is not motivating his team to maximize productivity, or some such nonsense, with the quota being a verbal mention never reflected in anyone's notes.