Since subscription under CSP channel is on monthly basis, how do we determine the renewal anniversary?

Though the payment term of CSP is monthly, when customer purchase licenses through CSP the subscription term is actually 1 year. Within 1 year the price and SKU customer ordered will not change, so even if a license is retired the customer can still continue to add/remove licenses until the end of the 1-year subscription term. At the moment there is no penalty if a customer cancels the subscription before the 1-year subscription expiry date. The renewal anniversary is 1 year from the subscription start date, which partner can determine through customer’s O365 admin portal.