It is by design that we don't populate the line item in Aria Cost reports, but we populate this value in the SKU Description column in the billing statement artifacts of tenants.
Any product name that a user enters in the billing rule will be recognized as the SKU description, not the product category.
SKU Description can be viewed from FlexReports.
Note: The PGB has a condition that adds a flat fee line on a specific day, but only if there is any usage recorded for that day.
In the provided example, a billing rule was implemented with Product name as "CUD adjustment". However, when reviewing the cost history, the specific product is not displayed individually. Instead, only a flat rate cost is shown. To view the cost associated with the product, you would need to utilize flex reports
Billing rule: Product Name: CUD Adjustment (Partner end)
Cost History: (Customer end)
Flex report: (Customer end)