The New Calendar is not the Gregorian. It is the Revised Julian Calendar. Which is actually astrologically more accurate than the Gregorian. Also the date is Pascha is calculated differently by the Gregorian than it is by the Julian Calendars. Both Julian Calendars calculate Pascha as the first Sunday after the first full moon after the Vernal Equinox. The Orthodox Pascha falls nearer to Jewish Passover than does the Western Easter.