business_management—Allows the creation of Business Managers
ads_management—Allows the ability to read and manage ad activity for admins and developers of the app
Ads Management Standard Access— Gives higher rate limits and allows users (who are not admins or developers of the app) to manage and create ad accounts.
Even though Ads Management Standard Access is optional, without standard tier access, certain features of the Marketing APIs cannot be used.
These permissions enable your app to create Business Managers on behalf of the end user.
If you need help with your 2-tier solution, see Support.