Scheduled Maintenance - These figures do not account for scheduled maintenance outages. Maintenance is required to ensure the fleet is up to date, secure and running smoothly. We perform this work during off-peak hours (at night), however it's still counted as "downtime" by the monitoring service.
Webserver Monitoring - Uptime data is based off the webserver status, not all services. It's possible for other services (email, mysql, etc) to be online during an "outage".
Polling Error - Our monitoring interval is 1 minute, so it's possible for sub minute outages to be recorded as a full minute.