The iSeries™ system attempts to allocate main storage as efficiently as possible. A job might not use the same amount of resources each time it is run.
For example, if there are several active jobs on your system, a job spends more time reestablishing the resources needed for running than if a dedicated system environment is used. The system uses the job and run priorities assigned to different jobs to assist in managing main storage. Therefore, high priority jobs can use less system resource than low priority jobs.
Because of these system operating characteristics, you might want to apply your own interpretation or algorithm to the job accounting data collected. If you are charging for the use of your system you might want to charge more for high priority jobs, work done during peak system time, or the use of critical resources.