Did you forget to change Derin in the Farm Mondays or is she purposefully there only one Day?
Well, yes. That's why I never claimed that my schedule was perfect.
It's just what I was using at the time I took the screenshot.
In this case, I had swapped Derin and Lillian on Monday the week before but I forgot to swap them back. You can also see that I forgot to reassign Charlotte to the Waiting Room on Saturday and I left Rita's Construction slots empty on Saturday and Sunday because I needed to borrow her for something else (I think it was for Tina's evaluation). And in case you are wondering, Megan was usually occupying the empty slots in the Monitoring Station, but I decided to keep her available because I had finished all research projects anyway. For the Restaurant I was usually assigning Sheila or Ruby to the evenings and Millie to the afternoons, but at some point I decided to shift Millie to the evenings and I left the afternoon slots empty (I don't remember why).
So this schedule could be optimized but it fills most slots and it is rather balanced, so that none of the girls builds up too much fatigue. Of course this also depends on who joins the expeditions: if I always send the same girls, then after a few days I have to help them relax at the Spa.