Hello Chad, so after looking this over with my team. The difference between these 2 MDA's most likely comes down to permissions of the 2 different analysis's.
The MDA created at the service level would only be visible for people that can see this service, via Management Zones, Environment permissions, etc.
Where the MDA created under the Diagnostic Tools would be available globally where everyone can see this view.
That being said if you moved the Services MDA to the global one under Diagnostic tools, you may have issue with migration