Marisa,
I don't see a category section in the grade section of the SCORM settings page as there are in quizzes and assignments, etc.. I am working in 3.1 on my MOODLE site. The work around I would use is to create the SCORMs then go to the gradebook setup of the administration section for the course. You will see a list of the assignments with the categories. Find the SCORM assignments and check the box on the left next to each one, then go to the bottom of this page to find the Move the selected items to: There is a dropdown of all the the categories and select the category you want these SCORM in (practice quiz results).
Hope that helps