Because Mule owns and hosts your Subscription Project, your database, your traffic, and your compute run on Mule's own accounts and on Mule's bill. That is why a monthly price has a data portion, and why heavier Projects cost more to run than light ones. Your data tier is set from what your Project actually does, and it is named on your quote.
Light. Up to 10,000 records, 5 seats, and 1 integration. This tier adds nothing to your monthly price. Above the allowance, overage is $15.00 per additional 10,000 records per month, and $5.00 per additional seat per month.
Standard. Up to 100,000 records, 20 seats, and 3 integrations. This tier adds $50 / mo to your monthly price. Above the allowance, overage is $12.00 per additional 10,000 records per month, and $4.00 per additional seat per month.
Heavy. Up to 1,000,000 records, 75 seats, and 8 integrations. This tier adds $150 / mo to your monthly price. Above the allowance, overage is $9.00 per additional 10,000 records per month, and $3.00 per additional seat per month.
Enterprise. Anything larger than the Heavy allowance. We price this with you directly and confirm it in writing before you sign. There is no automatic overage at this size.
Anything that syncs in real time, or more often than hourly, sits at the Standard tier or above, whatever its size, because it needs infrastructure that is always awake.
Mule will tell you before an overage charge first appears on an invoice. If your usage stays above your allowance, Mule may move you to the next tier up with 30 days written notice, and you may cancel before that change takes effect. A tier change changes your monthly price. It does not change your build portion, so it does not change your progress toward owning the Project.