Joke Collection Website - Public benefit messages - Why is the balance displayed on the main and secondary cards of telecom different?

Why is the balance displayed on the main and secondary cards of telecom different?

The balance displayed by the main and secondary cards of telecom can be different.

The primary and secondary cards share a package, which is charged monthly. Some of the fees currently displayed on the mobile phone will be exempted as a discount, so it is not accurate.

Data secondary card service is that users apply for a secondary card of the current mobile phone card. The secondary card has data function, and charging is incorporated into the main card of the mobile phone.