Opcode PCM_OP_RATE_GET_PRODLIST retrieves all purchased product for Service and Event combination
The below snippet from Documentation(7.4) BRM Documentation · Setting Up Pricing and Rating
Retrieving product lists
To get the list of products for an event, PCM_OP_ACT_USAGE calls the PCM_OP_RATE_GET_PRODLIST opcode. This opcode gets a list of purchased products (/purchased_product objects) for an account based on the combination of service and event type in its input flist. It returns a list of base products and valid customized products.
In its initial search for products, the opcode uses the event object and optional service object in the flist to determine which products it retrieves: