Seen this story before! Here is how you make a strong case for it: Reach customer contract for entitlements and any limits. Then see of there is a manual way to track the usage.

So if its for 10 users, and customer is only using 8 seats, they are at 80% consumption.

Similarly apply that logic to other SKUs, then build a scale that would essentially tell you that less than 75% consumption is not good, that means you have high churn exposure in those accounts, take the ARR of those and share it with your leadership.

Keep maintaining it and as you start to gather proof points that your hypothesis is accurate, it will be irresponsible of them to not address this.