OneWorld job queues can be configured to run more than one job at the same
time. This is controlled by the JDE.INI file on NT, by the RunOneWorld
scripts on Unix and by the standard queue configuration tools on the AS/400.
Your system is probably configured to run two simulatneous jobs in the
default queue (QBATCH or QB733x)
You have not included your platform in your email. If you have NT or Unix
take a look at this short document on the Knowledge Garden:
Document : oti-00-0110
Setting Up Multiple Batch Queues
There is also more detailed information in the Server Administration manual.