The appropriate choice of workload norms under controlled release can significantly improve the system performance in terms of the average time in system, average shop flow time and percentage of tardy jobs, relatively to an immediate release. This is mainly because controlled release is able to adjust the release decision, responding to stochastic events such as processing time variability. It is also expected that the improvement introduced by the controlled release process will become more significant with the increase of the system utilization. However, controlled release deteriorates system performance in terms of the standard deviation of the lateness (StDev lateness). This essentially results from the introduction of variability by the release process, due to the use of workload norms that may disturb the planned release sequence by holding back the release of some urgent jobs.