Hi Dan2 ,
To address your observation, the 120 requests-per-minute limit is enforced at the service principal level, not at the individual profile level. This means that all API calls made using any of the associated profiles, including the master, are collectively throttled under a single quota. Service principal profiles are designed primarily for organizational and tenant-level isolation, not for increasing or bypassing API throughput limits.
Regarding the 60 requests-per-minute cap you're observing per profile, even when tested in isolation this is not documented as a standard behavior and may be influenced by internal dynamic throttling mechanisms, tenant-level constraints, or load conditions specific to your environment.
To get a definitive answer about the throttling behavior you’re experiencing, particularly the 60 RPM limit, we suggest opening a Microsoft support case using the link below: How to create a Fabric and Power BI Support ticket - Power BI | Microsoft Learn
This will enable the Microsoft team to review backend telemetry for your tenant and provide an official explanation.
Hope this helps. Please reach out for further assistance.
Thank you.