Given that it wouldn't have made any difference to the overall leaderboard positions unless Robin gave Jorgie a 10 - and even then it'd have only meant she tied with Jen - I can't really see what the point of some quick maths would have been.
EDIT: OK, I should take into account that Jen hadn't skated at that point...but nonetheless, Robin couldn't have brought Jorgie's mark up higher than Chemmy and Chico's no matter what score he changed to.