It's a hypothetical scenario in which I'm the C prestige D1 team. I'm pretty sure the multiplier is more than 2x, and probably 3x, if not more? C v. D in D1 is a full letter grade, so that should be 2x already. If we assume D2 A+ < D1 D-, then the multiplier has to be over 2x and closer to 3x. Then throw in the possibility that D1 gets some kind of bonus, the multiplier could be much higher.
This is just guesswork on my part so if anyone can shed some light, it would be appreciated.