Clarification needed on Copilot Studio billing for agent flow actions (updated credit plan effective Sept 1, 2025). The doc states '13 Copilot Credits per 100 actions' with no charge for interactive M365 use. For cloud flows with fewer than 100 executed actions (e.g., 50 nodes in a run due to branching), is billing pro-rated at 13/100 per action (e.g., 6.5 credits for 50), or rounded up to the full 13? I've reviewed the billing docs and analytics dashboard, but it's unclear for partial executions.