When an employee of the Board, which is not an agency subject to 5 U.S.C. 7121(d), is covered by a negotiated grievance procedure, allegations of discrimination shall be processed as complaints under this part, except that the time limits for processing the complaint contained in §268.105 and for appeal to the Commission contained in §268.402 may be held in abeyance during processing of a grievance covering the same matter as the complaint if the Board notifies the complainant in writing that the complaint will be held in abeyance pursuant to this section.