Matters covered under sections 4303 and 7512 of this title which also fall within the coverage of the negotiated grievance procedure may, in the discretion of the aggrieved employee, be raised either under the appellate procedures of
section 7701 of this title or under the negotiated grievance procedure, but not both. Similar matters which arise under other personnel systems applicable to employees covered by this chapter may, in the discretion of the aggrieved employee, be raised either under the appellate procedures, if any, applicable to those matters, or under the negotiated grievance procedure, but not both. An employee shall be deemed to have exercised his option under this subsection to raise a matter either under the applicable appellate procedures or under the negotiated grievance procedure at such time as the employee timely files a notice of appeal under the applicable appellate procedures or timely files a grievance in writing in accordance with the provisions of the parties’ negotiated grievance procedure, whichever event occurs first.