I play the Kudos Challenge San Francisco level, which has has scores. Before I went in I had 51,116. When I left, with my score of 1,536 my score had increased to an amazing 51,216!! Why do I not get the amount of Kudos i actaully earn?

Hmm, did you already race on the level? I believe it will only add the new kudos you earned on top of the one's you previously earned.

So you mean if my previous score was 3,000 (the first time I take the run) I get 3,000 and if I get 3,001 I get 1? What happens if I get like 2,999? It gives me nothing? Well that would explain it, although I never really paid attention to that sort of thing.

because of the medal bias in the scoring you can actually see your score decrease!

If you were to score a 2nd place finish and a silver medal in a race earning 2000 kudos, a subsequent race finishing first (gold medal) and only 1600 kudos would cause your score to drop by 400, as the gold medal race is considered the more significant! sort of funny point-wise - not so funny if it causes you to lose a car (such as when you've just barely passed a landmark score and opened up a new car, which allows you to beat all the other cars in an earlier race - but just barely, and with fewer kudos. It happened to a friend and he was stuck for a long time - neither able to regain the points he needed to open his car back up, nor able to race fast enough to beat the the gold medal score. pretty funny huh? LOL