This research suggests emphasis manipulation on constituent skills of least-abled sets, improves coordination and integration of knowledge, skills, and attitudes on cognitive load, transfer, and instructional efficiency. The participants were divided into two groups. Competency levels for the designated skill sets were evaluated, and a pre-test was performed on both groups. The research applied an educational design based on individual learner's least-abled sets of constituent skills and identified the design's effectiveness on complex learning. One group was provided with the whole learning contents according to emphasis manipulation sequencing method, and the other group was provided personalized learning contents according to a method based on the least-abled sets of constituent skills emphasis manipulation. The group received materials constructed with emphasis manipulation, learned the whole constituent skills of learning contents and carried out conventional tasks. However, treatment group received materials constructed with the least-abled sets of constituent skills emphasis manipulation, learned only the least-abled constituent skills and carried out conventional tasks. This research suggests that teaching with the least-abled sets of constituent skills helps to reduce expertise-reversal effect and improve results of cognitive load, transfer and instructional efficiency.