Unable to update unit price item in Chargebee as an action flow in Zapier

Problem Statement

When creating a subscription via Zapier 2.0 you cannot enter Plan: Quantity (subscription_item[quantity]) and need to know when this field is required.

Solution

Plan: Quantity is mandatory when creating a subscription or adding an addon for flat_fee or per_unit price plans or items only. If you cannot enter it, check whether the plan or addon is metered billing—for metered billing plans or addons, this field is not mandatory.