Why? Seems like a reasonable amount. In the boxes i used there was place for i believe 80 tips so when i had to pipet something in a 96well plate with multiple components that where not able to be mixed before i sometimes got through multiple boxes in a single session. (And yes i wish i had a digital multi pipet but even then it would not have alwqys been possible to use it.
I would argue, that the reason why the cat choose this spot is partially because it is the deepest spot, eliminating the uncomfortable slope it would have if it sat 1 meter to the right. Thus there is a causation, the roof shape causes the cat to sit at this spot.