This base value comes from the component managing the actual monitored entity, such as a port's negotiated line rate, rather than being a fixed configured number, so it can change on its own. That means an event like a link renegotiating to a lower speed silently shifts what counts as 'over threshold' without anyone touching the interval profile. For example, a basis of 1000000000 on a port that just auto-negotiated down from 10 Gbps to 1 Gbps means the alert boundary recalculates lower even though the configured percentage never changed.