Indeed, most quizzing variables are updated after the second step of the process per slide. But a quizzing variable like cpQuizInfoAttempts is updated when an attempt starts immediately. I just wanted to warn you and offer you a way to check for yourself. There are still more quizzing variables, and was not sure that the score was the only one you wanted to track. I'm using those variables a lot in different blog posts, here some examples:
http://blog.lilybiri.com/intermediate-score-slides
http://blog.lilybiri.com/secrets-of-cpquizinfoanswerchoice-and