<p>I think 200-800 scale is insufficient for such subject tests. In case of Math 2, 10% of the test takers with 800 score are unable to demonstrate their true ability. Isn’t it impossible to put few very difficult problems and extend the highest score to 900 or 1000.
Some of good scorers can demonstrate their ability by taking AIME but it is not available for all students. Hm.</p>