I would argue that the literature is basically worthless here, because they're mostly looking at modulations around an absolutely ridiculous baseline. The 2003 changes dropped hours DOWN to 80/week and 16 or 28 per shift.

As an analogy, imagine reducing your cheeseburger intake from 60 per week to 40 per week: it probably won't have a huge impact on physical fitness.

The hand-off issue is also weird because it's at least theoretically improvable, whereas there's no real way (barring go-pills) to reduce sleep-related issues.