The Office 365 Service Level Agreement you have with Microsoft is difficult to manage. First it addresses only a small portion of what your users are actually using.
A few examples:
- For MS Exchange, SLA only concerns OWA. If you have E3 & E5 licenses with users only using Outlook, you’re out.
- SLA for OneDrive only guarantees the view and edit of file store
- Teams only guarantees instant messaging
You can always try to prove Microsoft wrong on the service they provide out of their data center, but you should probably focus on the service you deliver to your business lines.
The only way to manage Office 365 service quality really delivered to your business lines is to continuously use it, exactly as your users do, from where they are located.