This is an indicator that you are lacking in one of the areas (you are getting a different mix of questions from test to test and it is showing that you are lacking in one area that perhaps you are getting more on one of the tests).
Otherwise, I don't have a great explanation why your tests would be jumping so much up and down. I would not so much try to pinpoint the number of correct/incorrect questions but instead focus on the types of concepts that were missed (there could be multiple).
Your verbal seems to jump the most - any idea why that is?
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