Alpha bonnie is evaluating age at encounter start differently than QDM-based bonnie. It seems like it is using the date and the time of birth to evaluate if the patient makes it into the measure population or not. In our chart-abstracted measures, we do not use Time of Birth, only the Birth date to evaluate if a patient makes it into the population or not. Quite often, you will not even have the time of birth on an adult patient, and all that matters is the date.