This correspondence highlights that the Gibbs free energy description of a ferroelectric capacitor in series with a paraelectric capacitor, depends on the initial charge on the plates of the ferroelectric capacitor. An incomplete Gibbs free energy description, as in the original manuscript, leads to an incorrect simulation result. Therefore, a fully comprehensive analytical description and a corrected conclusion concerning the particular point of an increase in apparent coercive voltage in the steep-slope ferroelectric tunnel-FET, are presented.