When a user upgrades, do they
- receive an actual refund for the unused portion of their original sub in their original form of payment and then charged the full amount of the upgrade?
OR
- the unused amount of the original sub is applied to the upgrade subscription?
example: Original - $100 90% of the time is unused when they upgrade, which costs $200.
- is $90 refunded to the user in their bank account and then the user charged $200?
- the $90 is credited to the upgrade purchase and the user is charged $110 ($200 - $90)