The number of questions will always take into account all the questions, know that this can be very frustrating. A workaround offer is to avoid using that system variable cpQuizInfoTotalQuestionsPerProject that is used on the score slide, replace it by a fixed number if you want to show that (is it really necessary?). And please enter a feature request, I have been doing that already several times for this problem, but ... as long as only a minority of users is asking for it, will never be done.
Pretest questions are not counted, but those will not be an option perhaps?
Lilybiri