How does the Screen Time custom downtime schedule work in regards to spanning days?

I want to prevent my child from accessing their computer after (say) 9pm on school nights, but allow them to not have that restriction on a Friday or Saturday evening. While the Screen Time setting for Downtime does that, it is confusing as to how the schedule works when you consider wrapping from one evening into the next morning. For example, see this schedule: From this, I would presume that Sunday evening the downtime kicks in at 9:30pm. On Friday, the downtime would end at 6am and be disabled until Sunday comes around again. I noticed my child was on past 9:30pm last night (a Sunday; and yes, 'Block and Downtime' is ticked), so I'm wondering if that Sunday entry of "9:30pm to 6am" didn't apply to 9:30pm on Sunday until 6am on Monday or if it meant 9:30pm on Saturday until 6am on Sunday. The problem is that none of the guides I've found online seem to get into this detail and even Apple's documentation shows a custom where Sunday and Saturday are turned off, but doesn't explain how the hour mapping works. Is this the correct setting to block at 9:30pm on Sunday until Friday 6am, or is there another way to interpret how the schedule works? Or, is there some hack out there that the kids know about which defeats this mechanism (other than knowing the code to unlock)?