Why does the test result fluctuate between two adjacent tests when the same person is tested on the same instrument for the alcohol testing?

After drinking alcohol, alcohol is adsorbed into the bloodstream from the stomach. As time goes by, the alcohol in the blood will be adsorbed and digested. Alcohol is metabolized in the liver. Adult healthy liver can decompose about 10mL-20mL per hour of alcohol, so the blood alcohol content(BAC) may fluctuate within a few minutes.