Non-math guy speaks

This is from a guy who had to talk his way out of a D in physics in college (I was taking it credit/D/fail), but isn't the problem with Lauren's calculation just this: it relies on a proportionality that evaporates in later rounds. In the early rounds, with many games at ten points each, there are many different score levels one might come in at. What I mean is, if someone got 70% right in the first round and say there were a hundred points at stake (10 games x 10 pts per game), then one got 70 points. But in later rounds, where there are fewer point slots, doesn't that 70% rating Lauren gave you just turn into 50 points in the semifinal round (because - with 2 games x 50 pts pers game - in that round one can get either 0, 50, or 100 points, and nothing else). So if someone got only 60% right in the earlier rounds, shouldn't that also slot into the 50 point slot in the semifinal round? I can't express the point well, but it seems to me that her numbers will have to be way off because of this kind of thinking. If someone can explain to me why my thinking is d-u-m dumb, or can explain it better, I'd be grateful. Of course, Lauren is still a genius... for having so magnificently stroked Dodie's ego.