There's a clock in this scenario. It has a surprising number of effects to keep track of for a 1-5.
Unfortunately, we don't know exactly how this clock works. It's complicated.
I've made some decisions and some assumptions on how it should work. If you care enough to look into it and you don't agree with my conclusions, please feel free to download my source file, make some updates, and upload a competing version!
9-10_timekeeping.odt
9-10_timekeeping.pdf