Yeah go do 10, and miss out on all the social experiences you get at this stage of your life in exchange for more grades. What university is going to reject someone because they don't have more than 4 A levels? Are you actually insane? Some schools don't even allow their students to do 10 GCSEs. 10 As doesn't make you any better or more rounded of a person. More grades than the next person does not necessarily make you any more desirable. The only thing you'll be take in exchange for 6 unnecessary grades is some sort of arrogant self achievement that you are better than "average" people. How about instead of all those extra subjects, you go and get yourself a job, or some lengthy work experience, go and see how the world works. You can't learn everything from A levels.