The critical buckling stress in cold-formed structure design is important for calibrating EWM and DSM equations but is utilized differently. While DSM uses the exact numerical value of the whole section (interaction model), EWM builds effective width expression on discrete plate elements (element model), referred to as the analytical solution of elastic buckling stress outlined in Appendix I of AISI S100. In practice, AISI S100 allows using analytical solutions for DSM. However, it is observed to be over-conservative compared to numerical solutions for channel members bent about their asymmetrical axis. Although the design targets the ultimate strength, no report has been released on the effect of this redundancy on the ultimate strength. Thus, the present paper calculates the analytical and numerical buckling stresses of 16 prefabricated cold-formed channel sections of Lysaght and their corresponding DSM ultimate strengths and makes comparisons. The result shows that while the difference in the buckling stress can reach 26%, that of the ultimate strength is lower but still significant. This urges researchers to improve the analytical elastic buckling stress equation.