You cant say which they look at more, id say it is a combination of the two. If you have appalling AS's but are predicted 3As, it could be an indication of your potential...or your schools issues. Rather, i think a prediction that is close to your actual AS levels would set you in better stead towards gettin into the course you applied for. Meaning AS - BBC to a prediction of ABB would make more sense than one of BBC to AAA because retakes arent easy, and not everyone goes up after a retake.