In this work the superposition of effects with different diffraction origins and orders by formation of resulting magnetooptical response from the structures like magneto-photonic crystals in the regions far from plasmonic resonances were investigated for the first time. The contributions into magneto-optical response from diffraction and interferential phenomena in maxima of different orders in three-dimensional systems like magneto-photonic crystals were studied. It was demonstrated that the usage of integral response in order to analyze magneto-optical effects results in disappearance of interference phenomena. Diffraction maximum of the zero order reflects represent magnetic component of magnetooptical response. Numerical evaluations of observed effects were done.