5 U.S. Code § 3523 - Authority to provide voluntary separation incentive payments
(a) A voluntary separation incentive payment under this subchapter may be paid to an employee only as provided in the plan of an agency established under section 3522.
(b) A voluntary incentive payment—
(1) shall be offered to agency employees on the basis of—
(E) specific periods of time during which eligible employees may elect a voluntary incentive payment; or
(3) shall be equal to the lesser of—
(A) an amount equal to the amount the employee would be entitled to receive under section 5595 (c) if the employee were entitled to payment under such section (without adjustment for any previous payment made); or
(4) may be made only in the case of an employee who voluntarily separates (whether by retirement or resignation) under this subchapter;
(5) shall not be a basis for payment, and shall not be included in the computation, of any other type of Government benefit;
(6) shall not be taken into account in determining the amount of any severance pay to which the employee may be entitled under section 5595, based on another other  separation; and
 So in original.