We have first reviewed (1) the extremely bent molecular shape, (2) in-layer spontaneous polarizations near smectic layer boundaries parallel to the tilt plane in SCA*, (3) a difference in the molecular states of rotation about their long axes between SCA* and SC*, and (4) the ANNNI model with J(3) by Yamashita (C1P.12 (P-124) at this Conf.). Then we have observed the pretransitional effect in the tristable switching in three compounds and analyzed it through a thought experiment based on the above review; tilting directions in adjacent layers are concluded to be correlated with the biased directions of molecular rotation about the long axes. Finally we have presented evolution of switching characteristics from tristable to V-shaped in the first component compound of the mixture reported to show the thresholdless antiferroelectricity (Inui et al., J. Mater. Chem., 6, 671 (1996)), and discussed it in terms of the above thought experiment.