[sciurius]

I think [15/17 is confusing, but showing the duration in red to indicate that the setlist duration may be inaccurate is a good idea.

But what is a valid duration? All songs have a duration of 0:00 by default, which is valid. Separator items have no duration as well. OTOH it is straightforward to give separator items a duration of 0:01 to prevent them from colouring the total duration.