My student attends two classes — do the packs merge?

No, and that is the right answer. A student in two classes holds one pack per class, because the price and the session count belong to that class. Attendance in class A deducts the class A pack and never touches the balance in class B.

On screen, each class has its own pack card with its own balance and state — so a student can hold a healthy pack in one class and an empty one in another without either number masking the other. Parents see the same separation in the Parents Portal.