This study reports the influence of B-site acceptor dopants, manganese and copper, on the sequence of phase transformations in antiferroelectric (AFE) Pb(Zr0.60Sn0.30Ti0.10)O-3. The sequence of phase transformations below the Curie point have been examined by dielectric, polarization-electric field and strain-electric field studies. The parent compound and B-site Cu2+-doped composition exhibit the same sequence, FE AFE MCC with incommensuration in the multicell cubic (MCC) state, whereas in the case of B-site Mn3+-doped system, incommensuration is found to be suppressed and only ferroelectric (FE) phase is observed below the Curie point. The underlying mechanism is related to the nature of defect complexes present in the system through detailed Electron Paramagnetic Resonance studies.