You can create fixed discount rules, allowing you to easily apply these discounts when inviting a customer to a new product.
You create these discount rules (such as family discount, corporate discount, loyal customer discount, etc.) via My Company > Products > More > Discount Rules.
When creating a discount rule, you can specify the name and the discount percentage (the discount that the customer receives on the normal rate).
When you then assign credits to the customer via +, you can add a separate discount rule. The system automatically calculates the applicable rate.