Not possible if you want to use the original KC slides available since a couple of versionss. You could use the workaround that we needed before that feature: use normal quiz slide, set its score to 0. That means that you may need to use some advanced actions during Retake or Review status to skip the quiz slides that are now figuring as KC slides. Some quizzing system variables will take into account all questions, but the score and percentage will be correct.