While I saw in the video about grading schemes that one should be able to edit them (pencil icon), there is no option for a faculty member to do so in any of their courses.  The delete/remove icon is available, but the teacher really just wants to edit.  Is the reason they can't due to the fact that grades have already been assigned with this grading scheme?  (Even though the video indicated one could even delete a grading scheme and any grades that used it would still be OK).

I've attached a screenshot of the scheme the teacher is using... he reports he has been able to edit in the past.  Thank you for any advice you can offer...