Assigned is not the same as used
Microsoft 365 Copilot is billed per assigned license. In the admin center, the Microsoft Copilot usage report separates people who hold a license from people who used a feature in the window you pick: 7, 28, 90, or 180 days.
The per-person table shows last activity. Names can be hidden until an admin turns on names in the usage reports.
Look at 90 days before you remove a license
Someone who only opens Copilot at month-end can show zero activity over 7 or 28 days and still show up over 90. On a small team, ask whether that person is on leave or bunches their use into a few days before you treat the license as idle.
Removing the license in admin stops assigning it to that person. On an annual contract, the committed license count can stay the same until the renewal window. Check billing for when the count can actually drop.
The file you export yourselves
Export the usage report for the period and the Copilot invoice. That shows paid licenses against people who open it. We do not need access to the tenant.
An auditamia report gives a verdict from those files. If the export is missing, we say so and the figure stays an estimate. The same method covers ChatGPT, Claude, and the API: invoice plus use, and three actions for this week.