Joe,
With your files and your example renaming string, I get:
1427-JASD800170618
I expect something else is going on that isn't immediately apparent. Because this will require some interactive troubleshooting, I suggest contacting our support folks at:
By email: support@camerabits.com
By phone: +1 503.547.2888
Hours: Mon-Fri, 9:00am-5:00pm [PST/PDT]