The branching diagrams and the logistic function diagrams for the amplitude and phase functions of the incommensurate superstructure arising in ferroelectric crystals with unit cell multiplication n = 5 are investigated using the logistic function describing the doubling process. The parameters T and K, responsible for the long-range and anisotropic interaction, respectively, in the first approximation, well describe the behavior of the IC modulation and its modes. We found that at small values of the long-range interaction (T < 0.05), there is an undeveloped chaotic state characterized by blurred frequency doubling processes. Based on the logistic function diagrams, the influence of surface energy on the incommensurable superstructure causes an increase in the value of the anisotropic interaction, which leads to the degeneration of this system. The surface energy was found to transform the system from an inhomogeneous to a homogeneous state by changing the oscillation spectrum of the incommensurate superstructure phase function.