They replaced the old 5 level HPE ES performance markings with 3 just prior to CSC. The new ones were "Stalled" - you're expensive expect the bullet, "Driving" - we are making money from you but will still sack you when it suits us and "Accelerating" - don't expect a payoff to go yet as you are making us a profit.
Prior to the switch I had 7 consecutive "exceeds expectations" makings, the second level down and considered as a strong perormer. After the change, despite taking more responsibility for no extra salary, I was dropped back into the middle tier pot under a new system that makes it statistically more difficult to be a "top performer".
An ethical system would say, "If you achieve A you will get £x". The system they employ doesn't. It's all about talking up airy fairy notions with no objective measure. 5% is derisory when you consider that middle managers and above are on a far better promise than that and payment doesn't even depend on their individual performance. I got an unexpected £9k in 2015 purely by my boss switching my job code on promotion.
Finally anything you do get won't be consolidated into salary so it's a one-off and bonuses are no longer pensionable so you won't even get any benefit that way. As usual this is good for the headline but the reality is 95% will get bugger all. And we all know who the 5% are.