Consumption items are the representation of rated usage data within SAP Convergent Invoicing (CI), created from charged items sent by SAP Convergent Charging (CC).

The rerating process, triggered in CI, is used to recalculate charges for past usage due to events like price corrections. This process explicitly requires reversing the original consumption items and creating new ones based on the re-evaluated charges.

Preaggregation is a performance optimization function within CI that groups multiple consumption items into a single aggregated item before the final billing document is created. This process, by its very definition, operates on a set of existing consumption items.

A. The rating process in Convergent Charging creates charged items from raw usage data. These charged items are then sent to Convergent Invoicing to become consumption items; the rating process itself does not use them.

D. Billing plans are used for recurring or periodic charges (e.g., subscriptions). They typically generate billable items directly in Convergent Invoicing, not consumption items, which are specifically for usage-based charges.

1. SAP Help Portal, SAP S/4HANA, Rerating and Reversal in Convergent Invoicing: "The system reverses the consumption items that are affected by the rerating and creates new consumption items based on the charged items that are transferred again from SAP Convergent Charging." This confirms that the rerating process fundamentally operates on consumption items. (Accessed under the Convergent Invoicing section for SAP S/4HANA 2020).

2. SAP Help Portal, SAP S/4HANA, Aggregation of Consumption Items: "In invoicing, you can group consumption items before billing... The system summarizes the consumption items based on grouping variants that you define in Customizing." This document explicitly states that the preaggregation process groups consumption items. (Accessed under the Convergent Invoicing -> Billing -> Aggregation of Billable Items section for SAP S/4HANA 2020).

3. SAP Learning Hub, Course BR235 - SAP Convergent Invoicing: Unit 3, Lesson: "Explain the Structure and Source of Billable Items". This course material distinguishes between different sources of billable items. It clarifies that consumption items originate from an external rating system (like CC), while recurring charges from billing plans are another source, generating standard billable items directly.