In late 2020, International Maritime Organization (IMO) released interim guidelines on the second generation intact stability criteria. In this paper direct stability assessment in design situations using deterministic approach for parametric rolling failure mode is presented. A 3D nonlinear direct time domain method based on mixed-Eulerian-Lagrangian (MEL) scheme as opposed to impulse response function (IRF) method is used to simulate parametric rolling in both regular and irregular waves. Computed numerical results of roll amplitude in regular head waves is validated with other available literature results. This study further examines the influence of incident wave height and roll damping coefficient on computed heave, roll, and pitch motions in regular head wave conditions. Mean 3-hour maximum roll amplitude is obtained for design situations as recommended by the IMO guidelines.