Describe the issue

The invoice details for subscription contracts contain further details about the services billed. For usage-based scenarios, usage data may contain detailed information about these services. In the invoice details, these different sources are not retrievable.

Expected behavior

For billed Subscription Lines connetced to usage data, the invoice details should output information from the usage data instead of the Subscription Lines description.

Steps to reproduce

Use case
The user imports and processes usage data for quantity-based licencing and Azure consumption. The usage data for Azure consumption consists of multiple lines which are all assigned and billed via one single subscription.
For the customer, a separate contract is set up for support. The customer likes to get a combined invoice for both contracts.
After processing, the user creates a combined invoice which includes details about all the services billed.
The customer expects details about the support, the licences and the Azure consumption.

Repro steps

• Create two customer contracts, one for support and one for usage data, both with Invoice Details=Complete
• Create one vendor contract for usage data
• Set up Usage Data Supplier
• Set up master data for items (Subscription Packages, references) used in usage data.
• Create a new Usage Data Import and import files that include multiple lines for "Unit cost surcharge" and "Usage Quatity".
• Extend the vendor and customer contracts for all usage data.
• Extend the customer contract for support with the proper Subscription item
• Create a combined invoice for both customer contrats via Recurring Billing page
  Expected result: The combined invoice has three lines: consumption, usage, support. The details section shows the description of the "Support" subscription and information from usage data for the other two lines.

Additional context

Surcharge_1.csv
Usage_1.csv

I will provide a fix for a bug

• I will provide a fix for a bug