A quick follow up: I have a question about how the do-not-disturb switch setting relates to the timer for automatically turning on and off do-not-disturb feature.
I can imagine two possibilities:
1. The do-not-disturb switch turns on or off the entire do not disturb feature, including the automatic time-of-day on/off timer feature.
2. The do-not-disturb switch does not affect the automatic time-of-day on/off timer feature, and in fact the timer flips the do-not-disturb switch on and off at the indicated times. That is, the do-not-disturb switch is a continuous indicator of whether the device is or is not in do-not-disturb mode, regardless of whether the timer, or you manually, put it into that mode.
I think it's the second of the two: that is, it appears that the switch does not affect the timer, but the timer does affect the switch. So, for example, if I set it to go into do-not-disturb mode at 10PM, and the switch is off at 9:59PM, then at 10PM, the switch will automatically flip on at 10PM. That as opposed to the switch being off disabling the entire do-not-disturb feature, including the timer, thus preventing it from going into do-not-disturb mode at 10PM.