It’s possible that usage-based products can be subjected to the amendment operations such as “Change” or “Cancel” in Conga. Although Billing allows you to perform amendments on usage-based legacy assets, it imposes some timeline restrictions which are as follows:

• You can perform the said amendment operations either on the “Start Date” of the ALI, or from the “First Billing Date” onwards.
• If you attempt to amend the asset line item between the “Original Start Date” and the “First Billing Date”, the system does not accept it.
• If you want to debit or credit some amount to a customer "between the Start Date and First Billing Date”, you need to do it manually.

You must not change the First Billing Date manually or through the database updates for subsequent operations. If you do so, it results in serious data corruption which may impact the billing data integrity.