This Part shall apply to all annual salaried employees in the Professional, Scientific and Technical Services Negotiating Unit in the competitive, noncompetitive, exempt and labor classes whose positions have been allocated to a salary grade (other than grade 38), and other employees whose positions are unallocated but are equated to salary grades by the Director of the Budget. Excluded from coverage for the purpose of performance advances are those employees whose positions are both unallocated and not equated to a salary grade, those employees in positions allocated to grade 38 and those employees paid on other than an annual salary basis.