I was able to resolve the issue after watching the instructional video on YouTube by WP Plugins from A to Z . (That video can be seen here for anyone wanting to learn how to use this plugin.)
I was entering the times incorrectly, not realizing that 1:30 AM is entered as 1:30, while 1:30 PM is entered as 13:30.
Thank you again for your plugin. I appreciate it even more, now that I have a better understanding of how to use it properly.