In the %ile est column, from answers 11 to 14, i have got 98% on answering correct questions. When I got question 16 wrong, my %ile est dropped drastically to 79%. Question 15 was in difficulty range of 700-800. This pattern has been represented many times in the paper, i.e., the %ile est drops from 98% to around 80% with only one wrong answer. After answering so many questions right, does answering one wrong question, that too of high difficulty, penalize so much?