The working of a Scheduler seems confusing. Can you explain it?

Consider this image from a Scheduler screen.

Consider the parts of the screen highlighted in red.

• The Workflow job has sequence number 0, frequency 00:00, and is active. Therefore, it is given first priority and executes instantly.  
• The Recurringinvoice has sequence number 1, frequency 12:00, and is active. It was last scanned 10 hours ago. The scheduler will wait for 2 more hours before executing at the frequency 12:00.
• The SendReminder has sequence number 2, frequency 00:00, but is inactive. Hence it will be skipped by the Scheduler and moved to the next job.

To know more about Scheduler, click here.