Only the first title should be converted to from sort to display order. Subtitles don't influence display order, so don't need to be touched. OK, I now have a subtitle with a comma ('Ring the Bell, Watchman'). If it was the main title I'd have to do something else, but it isn't, so for now...

This book provides the dots for the music to all the dances
performed by Cry Havoc. The name of the dance is given as the tune title.
If the name of the tune differs from the name of the dance, the tune
name is given in the subtitle.