Same to me. Once I got 670 on CR but in subsequent practice tests, my score just ranged between 570 to 630. (Sometimes this low score is caused by vocab, but most of the time there are other reasons). Perhaps I'm using too much intuition and sometimes crossing out 'right answers'. I'm not sure if I have credits to give you advices, but make sure that you don't assume anything. The answer is ALWAYS found in the passage and can be DEFENDED by context.