Uptime Institute’s Tier guideline is not an official accredited standard and neither does it have an official accreditation scheme whereby audits conducted are having oversight from an accreditation body. Uptime conduct the Uptime Tier Topology assessment themselves and print their own certificates.
This is an evident conflict of interest and bias which is prohibited by standard organizations such as ISO. Accredited standards under ISO have a clear definition to avoid conflict of interest by separating the SDO (Standards Development Organization) from the AB (Accreditation Body) and the auditor/CB/CAB (Certification Body/Conformity Assessment Body).