Business Week and US News have never reported average TOEFL scores at the top universities. The schools content themselves to indicate minimum requirements on the test to satisfy English language requirements. As such it is probably fair to conclude that obtaining the school minimums is sufficient, and an extra ten points on the TOEFL does not carry the same weight as extra ten points on the GMAT or GRE. However, do at least achieve the minimum score, or schools will expect you to take the test again. Arguing with a school representative that the three years spent working in London should exempt you or excuse the missing three points on the test will not work. Your time would be better spent brushing up on your English and hitting 250+.