Hi John

We will get the documentation updated to explain about historical course completions

Totara has certifications where the same course is completed periodically - the old course is archived when the course has to be done again rather than when it is reattempted 

It isn't possible to move a current completion record to a historic record with the course completion editor or through the upload completion records. We do have a feature request TL-21232 for this.

If the user is unenrolled form the course It is possible to delete their current completion record in the course completion editor and the record can be uploaded to the historic completion if required.

Regards