How does the premium pass system work?

Premium pass subscription privileges are tied to the platform account (Apple Account or Google Account) you subscribed to the plan with, not the app save data.
Therefore, the following conditions must be met in order to use the premium pass service:

For Apple Accounts
• The Apple Account you subscribed with must be selected in the App Store.
• The app must be installed while the Apple Account you subscribed with is selected in the App Store.

For Google Accounts
• The Google Account you subscribed with must be selected in the Google Play Store.
• The app must be installed while the Google Account you subscribed with is selected in the Google Play Store.

You can only subscribe to the premium pass with one save data per one platform account.
If you wish to subscribe to the premium pass with multiple save data, you must use multiple platform accounts.

Transferring Premium Pass Privileges
• If you attempt to subscribe to the premium pass with a different save data or attempt to Transfer Pass Privileges using an Apple Account or Google Account you've already subscribed to the premium pass with, your premium pass subscription privileges will be transferred.
• If your premium pass subscription privileges were transferred to another save data, you will temporarily be unable to re-transfer them from that save data to another save data (including the original save data) for 60 days.
Note: Please be careful if you are using one Apple Account or Google Account on multiple devices.

You can attempt to return subscription privileges to your original save data by using Transfer Pass Privileges after the period during which you cannot transfer is over.
You can check how long the period you cannot transfer is by attempting to Transfer Pass Privileges.

Note: Please see How can I Transfer Pass Privileges? to learn how to do this.