The FvCB model is more complicated than it looks for parameter estimation. It has several characteristics that invalidate the use of conventional optimization approaches . For example, the FvCB model is a change-point model and is structurally overparameterized in individual carboxylation limitation states with respect to A/Ci measurements. Without recognizing these unique features of the FvCB model, conventional approaches may lead to incorrect parameters and produce false parameter relatinships. EDO takes into consideration the unique structure of the FvCB model and is better suited for analysis of A/Ci curves. For more details, please read Gu et al. (2010).