Exact Extracts from Salesforce Billing Implementation Guide:

“Billing Type determines when a customer is invoiced and charged for a subscription or service. You can set Billing Type to Advance or Arrear.”

“Advance billing collects payment before the service period begins. The invoice is generated prior to the start date of the service period.”

“Arrear billing collects payment after the service has been delivered.”

Step-by-Step Reasoning:

Requirement: The finance team wants invoices to be sent before the service begins (on the 15th of the prior month).

Advance Billing Type: Ensures that invoicing occurs prior to the service period start, aligning perfectly with the “collect before service” requirement.

Arrear Billing Type: Would bill after the service delivery, which does not meet the requirement.

None: Would result in no defined billing schedule, leaving the invoicing behavior undefined.

Therefore, Advance Billing Type is correct.

References :

Salesforce Billing Implementation Guide — Billing Treatments and Billing Type

Salesforce Subscription Management Implementation Guide — Invoice Timing and Billing Configuration