If they predict you any GCSE results based on your KS3 levels, ignore them completely. They're mainly there so that the teachers have something to compare the work you're producing to the level of work you (apparnetly) should be producing, then if you aren't, they start whingeing at you. e.g. in History I was working at level 8 in KS3, but was predicted an A from my 'Yellis' test. So when I got Cs and Ds on tests throughout year 10 and 11, my teacher really kept on at me. But in the end, I *somehow* got an A, so....I really wouldn't worry too much about predicted grades, the grades your work is at and the grade you eventually get can be so different.