— This paper proposes the first automatic approach to simultaneously generate Cycle Accurate and Cycle Count Accurate transaction level bus models. Since TLM (Transaction Level Modeling) is proven as an effective design methodology for managing the ever-increasing complexity of system level designs, researchers ploit various abstraction levels to gain either simulation speed or accuracy. Consequently, designers repeatedly perform the time-consuming task of re-writing and performing consistency or different abstraction level models of the same design. To ease the work, we propose a correct-by-construction method that automatically and simultaneously generates both fast and accurate transaction level bus models for system simulation. The proposed approach relieves designers from the tedious and error-prone process of refining models and checking for consistency.