Looked at another way, I was docked because I consistently outperform estimated time to delivery, which means the company actually makes more money off my work because we charge our customers for development work.
So, what do I think of performance appraisals at my work place? I'm actively looking for other work.
I also believe that performance appraisals, for anything but bottom rung employees, are currently done one way only. They should be done from both perspectives. The managed employees reporting to the managers boss. This way, ineffectual middle managers can be disposed of.