Acquiring computational modeling and simulation skills has become ever more critical for students in life sciences courses at the secondary and tertiary levels. Many modeling and simulation tools have been created to help instructors nurture those skills in their classrooms. Understanding the factors that may motivate instructors to use such tools is crucial to improve students' learning, especially for having authentic modeling and simulation learning experiences. This study designed and tested a decomposed technology acceptance model in which the perceived usefulness and perceived ease of use constructs are split between the teaching and learning sides of the technology to examine their relative weight in a single model. Using data from instructors using the Cell Collective modeling and simulation software, this study found that the relationship between perceived usefulness-teaching and attitude toward behavior was insignificant. Similarly, all relationships between perceived ease of use-teaching and the other variables (i.e., perceived usefulness-teaching and attitude toward behavior) became insignificant. In contrast, we found the relationships between perceived ease of use-learning and the other variables (i.e., perceived usefulness-teaching, perceived usefulness-learning, and attitude toward behavior) significant. These results suggest that priority should be given to the development of features improving learning over features facilitating teaching.