An employee as defined by
section 2105 of this title or an individual employed by the government of the District of Columbia, who is separated from the service, is transferred to a position described under
section 6301(2)(B)(xiii) of this title, or elects to receive a lump-sum payment for leave under
section 5552 of this title, is entitled to receive a lump-sum payment for accumulated and current accrued annual or vacation leave to which he is entitled by statute. The lump-sum payment shall equal the pay (excluding any differential under section 5925 and any allowance under section 5928) the employee or individual would have received had he remained in the service until expiration of the period of the annual or vacation leave. The lump-sum payment is considered pay for taxation purposes only. The period of leave used for calculating the lump-sum payment shall not be extended due to any holiday occurring after separation. For the purposes of this subsection, movement to employment described in section 2105(c) shall not be deemed separation from the service in the case of an employee whose annual leave is transferred under section 6308(b).