How about we use levels to figure out /peaceful. If you are level 1 you can have /peaceful on all the time. If you are level 2 you can only have /peaceful on for 23 hours of play time. on the 24th hour it is reset to /peaceful off for a full hour of play time. then you can go back to /peaceful on. if you are level 3 you can have it on for 22 hours of play time at a time. and so on until you are level 25 then you can't have /peaceful on at all.
If by chance you are say level 3 and you decide to turn peaceful off though you've been on peaceful for 11 hours once you turn back on peaceful it starts again from that 11 hour period. Understand?
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Y'know sometimes even my lucky rocketship underpants don't even help.