I work in the lab of the author of this study. I can tell you that this was also a concern of the high school students; they were given a questionnaire about wh

I work in the lab of the author of this study. I can tell you that this was also a concern of the high school students; they were given a questionnaire about when THEY would like to start school, and they only wanted to shift start times by about half an hour for this very reason, and were concerned about when to compensate for the time, preferring shorter breaks than ending later. Fortunately for them, Swiss high school schedules are crazy with lots of big gaps, so improvements can be made to start times before sacrificing end times.