OK. Hear me out. There's an assumption here that OSU is going to outperform Iowa offensively.
Yes, this is a reasonable assumption.
But....
It's theoretically possible that Iowa has more offense (or, I would think their defense is good enough that they could limit OSU's offense to something like 200 yards and Iowa gets lucky).
So, under that scenario, should we put a negative number? Or is it just the difference between the two and if Iowa outperforms OSU, it's still the positive number that you are counting?