You have me confused. If you drink on a "daily basis" then the 11 beers you drank days before are far less significant that what you drank the day before the test. This is providing the test is for EtG.
The sample you provide monthly might be tested in various ways. But a monthly sample signed and directed to a laboratory is slightly in favor of EtG as opposed to ethanol testing.
Based on the information provided, I couldn't come within 150 miles of an assessment.
The elimination rate for alcohol is well established (within boundaries). Following is a link to a reasonably accurate calculator predicting time of elimination based on number of drinks consumed, considering size and gender across time. See
BAC calculator.
Please note that amount of alcohol consumed, therefore the BAC level, cannot be directly correlated to the level of EtG produced or elimination time. (Example, see
Borucki, 2005)