As an update, I believe I figured out the problem. In the App Settings > Roles > Viewer screen, I had to set Table access for the student information table under the View column to All Records. The viewer role was set to view none, because I didn't want everyone to be able to see all the other students. I believe because of the restriction, when the summary field on the class table of number of students would always read 0, and because of that the available spots formula column (Max_Students - Enrolled_Students)would be calculating (Max_Students]-0) and always displaying the maximum capacity of the class.
So now it works, and I've removed the link to the Registration table from the form so it cannot be clicked to see every registered student and their information, but should I be worried that because the viewer has the permission to view everybody that somehow they will be able to?
