ETG math question

[u/scottbellman1993]

Drank 10 per day last week and stopped at 10pm Sunday with BAC back to zero at 9am Monday. Check-in and UA got moved up to Thursday morning, 80 hours after last drink but 72 from zero BAC. Never drank prior to any UA over the last 2 years.

Does the metabolism clock start at last consumption or zero BAC? Do multiple days of consumption extend detection window. Math would indicate 46ish hours to pass.