latencyQuality

Estimated, not Exact, and the distinction is deliberate.

The host time CoreAudio reports covers the audio unit's own buffer accurately. The full signal path can add more: the device's safety offset, and on a Bluetooth or AirPlay route a large and variable transport delay. Summing those means reading several device properties and following route changes. Until this sink does that, Estimated is the honest answer, and the engine widens its tolerances rather than trusting a figure that may be short by tens of milliseconds.