When creating or editing a category, you can enable the “Cumulative Packages” feature. This option allows you to offer discounts to users based on the packages they have previously purchased.
If a user buys Rank A for 10 USD, it essentially acts as a 10 USD credit. Now, if you apply a 50% discount to Rank B, reducing its price to 10 USD, the user can upgrade to Rank B for free. The 10 USD they initially spent on Rank A is credited back, allowing them to purchase Rank B without additional cost.
In the Advanced Settings section, check the Cumulate the purchases inside of this category so customers only pay the difference when purchasing a higher priced package. box.
Save the changes.
Subscriptions do not support cumulative packages. If you plan to offer subscriptions, this feature cannot be enabled for the category.