That's interesting, I never realised "stuff up" was a British/Australian-ism.
When I stuffed up (Friday Week 3), Elsa & Demi Salas had 6 YA kids who had successfully moved out. That doesn't include the two that forgot to get jobs first. No kids left in the house - Elsa isn't due to give birth again til tomorrow. So I think that makes a total of 9600.
My first YA moved out on week 2, day 4 (Wednesday) shortly after she got back from school that afternoon but unfortunately I forgot to make a note of the exact time. Feel free to call it 12am Thurs or whatever you think is appropriate, in the unlikely event that it becomes necessary for tiebreak purposes.
I think I'll play out the last week unofficially at my leisure to see how things would have panned out if I hadn't stuffed up. Though the odds seem high that I'd likely have stuffed up something else later on instead. Clearly I need to find some mathematical diagrams for my walls as concentration/focus is not my strong point...