Stress Level - History vs native widget value

Does anyone know what the native widget shows as stress level? Is it the days avarage? Avg of the last 4 hours? Something else?

I implemented stress level in my WF and display the newest value but based on some user feedback this value does not fit the widgets value.

I actually would like to show the same value as the widget... How could I do this? I don't own a device that supports CIQ system 5 so I can't compare the values on a real device myself..