SCORM modules added from file system repo are not updating when file/s replaced in repo.

Instructions were followed from:
http://danmarsden.com/blog/2013/09/24/managing-scorm-content-in-moodle-2-6/

Essentially:

1. Save zipped SCORM object to file system repository directory that you have created under moodledata folder
2. Create new activity in Moodle, selecting SCORM package.
3. Use file picker to choose SCORM object from file system repository you set up (make sure to select Create an Alias / Shortcut and assign Auto-Update to Every Time It's Used or Daily)
4. Go through lesson/quiz to completion.
5. Make change to SCORM object and save updated file in repository directory (renaming or deleting old file).
6. Enter lesson again to check if update occurred (or after cron job run if Daily selected).

Current result is no change to the SCORM object when accessed either minutes later, hours later or after cron job.

Appears file is either a) not being checked properly for difference - although it does appear to be based on code or b) is being checked for difference but still not parsing this information correctly and retrieving the updated file.