Hi,
I've been told that "Exit activity" in Moodle must always be clicked for a SCORM file to be completed.
Is that true?
(Having trouble with getting consistent completions)
Not in my experience. There are a lot of ways to exit a module (including an exit button built in) and it should report regardless. Also, you can click Exit activity and not be complete. It isn't a completion trigger. But it's possible it might be interfering for some other reason.
Great, thanks. We can rule that option out then. 
A quick supplemental question:
Is it best to have Auto-commit enabled as a default?
A quick supplemental question:
Is it best to have Auto-commit enabled as a default?
That is open to opinions. I never do. I'm sure it is there because someone uses it and finds it extremely helpful. Now that I'm looking at it (again)...it might help. I do not force completion, as that can cause trouble but auto-commit might be helpful.