Job release is not a once a day process.  If you have a relatively high volume of multi-level jobs, jobs should be released periodically throughout the day after finished items are received so that higher level jobs can be released in a timely fashion as subassembly jobs get completed.  

Releasing jobs is a simple process that is a big time-saver because it eliminates all the manual investigation that would otherwise be needed to determine which jobs are completed and which ones are to be started next.