Recently, we have predicted, solely on the basis of symmetry arguments, the existence of strong magnetochiral anisotropy in the displacement current in chiral dielectrics and reported its experimental observation in chiral ferroelectrics near their ferroelectric-paraelectric phase transitions [Nat. Commun. 13, 3564 (2022).]. Here, we present a microscopic model that describes both direct and inverse dielectric magnetochiral anisotropy (dMChA) in the chiral ferroelectric triglycine sulfate (TGS), based on the specifics of the charge movement in a time -varying electric field. We predict a strong inverse dMChA in TGS that should be within reach of experimental observation and we find good agreement between our model and the experimental observation of the direct dMChA in TGS.