For employees who have been regularly working a shift described in Section 8 for thirty (30) or more calendar days immediately preceding a paid holiday, or the commencement of a vacation, or the commencement of a paid sick leave period, or compensatory time off, as the case may be, the applicable differential shall be included in such employee’s holiday pay, vacation pay, paid sick leave or paid compensatory time. The vacation, sick leave, holiday and compensatory time off pay of an employee on a rotating shift shall include the differential such employee would have received had they been working the same shift during such period.