Admin users can set the churn formula under Data Platform > Data settings > Subscription Analytics.
Quantity Churn Rate is the rate at which your customers are canceling their subscriptions or reducing the number of licenses/seats (their subscription-quantity value).
What analysis can be gained?
For many types of subscriptions, the quantity value will just be one. However, if you sell subscriptions with multiple seats, then this measures the rate at which this subscription-quantity value is falling. This enables you to view the rate at which seats are canceled, rather than customers.
How is it calculated?
This depends on whether you use the B2B or B2C churn rate formula.
You can learn more about the two formulas and how they affect the Quantity Churn Rate in our Churn Rate Formulas Documentation.