Cringe-worthy because I realize this obscure fact likely lead to dozens of wrong reports in my career. The problem starts with a question from Derek about why his DSUM formula is not working. It seems to be a bug, but other Excel MVPs say it is working as designed. Then @ExcelisFun makes it even worse by telling me that Advanced Filter has the same design! Watch how both DSUM and Advanced Filter both seemingly return wrong results. Then, a workaround to get exact match in the criteria range. Finally, a plug for the new Excel MVP book available at Excel Insights book by Excel MVP