As described to me, the bell curve was shifted down prior to the review process.
Curve described to me wasn't anywhere close to "inconsistent" in the majority but idk it might vary between groups. Anyway, the the rating process isn't actually an objective measure of your performance, it's a comparison against your peers. A leader of a universally strong team still needs to pick a few people to screw. The screwing quota was increased this year due to poor company performance.