The proposed model in our previous study(1) improves the mathematical approximation defect and gives a new expression for the configurational energy of mixing using the fractional form rather than the algebraic form with second-order approximation for the configurational energy of non-random mixing(2). In this study, we introduce new universal constants to take into account the chain length dependence of a polymer in a solvent. Our proposed model shows a slight discrepancy when compared with experimental data and gives a better understanding of phase equilibria dependence on the chain length of the polymer.