((a)) ** In general** Appropriations available for the pay and allowances of commissioned officers of the Service shall also be available for the pay and allowances of any such officer on active duty while attending any Federal or non-Federal educational institution or training program and, subject to regulations of the President and to the limitation prescribed in such appropriations, for payment of his tuition, fees, and other necessary expenses incident to such attendance.

((b)) ** Voluntary separation within period subsequent to attendance** Any officer whose tuition, fees, and other necessary expenses are paid pursuant to subsection (a) while attending an educational institution or training program for a period in excess of thirty days shall be obligated to pay to the Service an amount equal to two times the total amount of such tuition, fees, and other necessary expenses received by such officer during such period, and two times the total amount of any compensation received by, and any allowance paid to, such officer during such period, if after return to active service such officer voluntarily leaves the Service within (1) six months, or (2) twice the period of such attendance, whichever is greater. Such subsequent period of service shall commence upon the cessation of such attendance and of any further continuous period of training duty for which no tuition and fees are paid by the Service and which is part of the officer’s prescribed formal training program, whether such further training is at a Service facility or otherwise. The Surgeon General may waive, in whole or in part, any payment which may be required by this subsection upon a determination that such payment would be inequitable or would not be in the public interest.

((c)) ** Training in leave without pay status** A commissioned officer may be placed in leave without pay status while attending an educational institution or training program whenever the Secretary determines that such status is in the best interest of the Service. For purposes of computation of basic pay, promotion, retirement, compensation for injury or death, and the benefits provided by sections 213 and 233 of this title, an officer in such status pursuant to the preceding sentence shall be considered as performing service in the Service and shall have an active service obligation as set forth in subsection (b) of this section.