In the study of the transition dynamics, we found that the reflectance of bistable cholesteric displays depended on the addressing sequence of the bipolar pulses. Two different pulse amplitudes corresponding to the high and low voltages about the quiescent point were chosen. By a proper permutation of such pulses, the final reflectance of even difference could be obtained for gray-scale display applications. In contrast with the root-mean-square (rms) modulation techniques, this scheme proposed for the first time does not primarily depend on the rms voltage. In this paper, we study the electro-optics and the domain characteristics, and propose a phenomenological proposition to describe this effect. We shall also extend our previous driving scheme to demonstrate the gray-scale control at 5 ms/line addressing.