There is only one subscription Account Owner for an Organization. 

The Account Owner controls the subscription plan.

Depending on the Owner's plan level they maybe able to customize their Organization's branding and assign Uploader privileges. My Profile for Account Owners will include an Organization tab.

Account Owners will get all notifications and full course visibility for courses within their organization.

Account Owners are sometimes referred to as Course Owners because they own all the courses in their Organization.