The Arab Open University (AOU) has adopted the standard deviation method (SDM) as a grading system in replacement of a fixed scale. Adopting SDM was intended to remedy a problem that has resulted from discrepancies between AOU's graduation requirements and those of its partner, UK Open University. This paper aims mainly at investigating whether SDM has served the purpose for which it was selected. A data set of the final letter grades of students enrolled in 18 licensed courses from UK-OU at Kuwait branch was used. These letter grades were analyzed in comparison with the letter grades that would have been assigned to students had the fixed grading scale been utilized. The results of the comparative analysis revealed that SDM resulted in benefiting 39.4% of all students and lowering the letter grades of 10.4% of the students. Despite its positive results, SDM has not contributed significantly to remedying the problem in question. Thus, a case for withholding the D grade while continuing with using SDM was presented. (Contains 9 tables and 1 figure.)