Hoi,
When I want to pick up a new song, I'll take a quick look at the lessons in the tutorial of that song, see if it interests me and if I'm capable of learning it. If not, the progress indicates nevertheless "tutorial completed" or "x of y lessons watched", which isn't of course the case.
Of course I can hide that specific song, but it seems more UX friendly if I can unmark that specific tutorial as completed.
Just a thought.
Grz
Dirk