Why do I have both Guard Premium and Guard Standard subscriptions on the same Atlassian site?

[Andy Gladstone]

Hi Community! I am hoping you can help me understand why I have both Guard Premium and Guard Standard enabled/billed on a single Atlassian site.

As of today, I am being billed for 254 Product-users for Atlassian Guard Premium. I am also being billed for 185 active users for Atlassian Guard Standard. 

We have 356 Managed Users total in our organization. 

Why the discrepancy in billing? And why need both? How can I be sure that of the 254 being billed for Premium none of them are ALSO being billed for Standard?

Please provide an explanation, not just a link to an Atlassian Support Article. I need the community to help me understand this.

Thank you!