Atlas Dedicated Cluster vs Shared/Flex Cluster Storage Pricing

Hello,

I understand that shared/flex clusters price storage based on uncompressed data+index usage, as per below documentation. However, the wording makes it seem specific to shared instances. Does the same billing method apply for dedicated clusters M10+ as well, or is it instead based on totalStorage() which factors in WiredTiger compression?

https://www.mongodb.com/docs/atlas/reference/faq/storage/

How does Atlas calculate storage limits for Flex Clusters?

Atlas calculates the storage limit for Flex clusters based on data usage, as opposed to the storageSize metric used by non-Flex clusters (which includes compression). Atlas determines data usage by summing a cluster’s dataSize and indexSize. You can issue the db.stats() method to view the values of these fields.

Thanks for replying, although it is still unclear.
For example, on an M2 shared cluster, the 2GB data inclusion will be measured against dataSize+indexSize, right?
For a M10 dedicated cluster, can you confirm the size of the provisioned disk means storageSize()?

I’m trying to understand how Atlas decides how much storage I’m using, and in effect how my billing will be affected between Flex and Dedicated clusters