Summary  

When you edit a subscription mid-term to add a contract term and there are unbilled charges for the subscription, the default behavior in Chargebee is to invoice the unbilled charges while adding the contract term. 

Solution

If you don't want them to be billed immediately, then this can be achieved only via API. You need to call “Update Subscription API” To update contract terms without adding unbilled charges in Chargebee, you can use the invoice_immediately parameter and set it to false when changing the subscription. This will prevent the unbilled charges from being billed immediately.



These unbilled charges will be automatically invoiced in the upcoming subscription renewal or contract renewal date. You can learn more about its unbilled charges here.