I'd like to suggest the scores of a play that resulted in a fail/quit would be saved if it were higher than the previous high score. For example, you do a song with nofail and it saves as a completed score. You then try it but fail halfway, and that saves as a DNF if it's higher than the previous score. If you do the song at a later time and finish with a higher score than your DNF and old high, it overwrites both.
Example:
> rrwhitezi plays Big Black on nofail and gets 1000 points
> Score registered as high score
> rrwhitezi plays Big Black but fails halfway at 5000 points
> Score registered as DNF score
> rrwhitezi completes Big Black with 10000 points
> Score overwrites both DNF and the original high score
Example:
> rrwhitezi plays Big Black on nofail and gets 1000 points
> Score registered as high score
> rrwhitezi plays Big Black but fails halfway at 5000 points
> Score registered as DNF score
> rrwhitezi completes Big Black with 10000 points
> Score overwrites both DNF and the original high score