Microsoft has pushed the general rollout of usage-based billing (UBB) models in Copilot back by about a month. In a November 4 update to Message Center post MC1519122, the Frontier preview runs from early to mid-November, but general availability now begins in early December and completes by mid-December — previously it was slated for early to mid-November.

The models arriving under UBB are not minor: GPT-6 Astra and Claude Fable 5.1 will be generally available as usage-billed models in Copilot Chat and in Word, Excel and PowerPoint via the model selector. Microsoft also says users will be able to set the reasoning effort level when using a UBB model in Chat.

Separately, Microsoft's partner guidance confirms usage-based billing will be enabled by default starting December 1, 2026 for new Microsoft 365 Copilot Business licenses bought through CSP. For organisations budgeting Copilot, the billing model is changing on a schedule that has already moved once.