((a)) Physician assistants and expanded-function dental auxiliaries shall be entitled to additional pay on the same basis as provided for nurses in .

((b))

((1)) When the Secretary determines it to be necessary in order to obtain or retain the services of individuals in positions listed in , the Secretary may, on a nationwide, local, or other geographic basis, pay persons employed in such positions additional pay on the same basis as provided for nurses in .

((2)) Health care professionals employed in positions referred to in paragraph (1) shall be entitled to additional pay on the same basis as provided for nurses in .

((3)) Employees appointed under performing service on a tour of duty, any part of which is within the period commencing at midnight Friday and ending at midnight Sunday, shall receive additional pay in addition to the rate of basic pay provided such employees for each hour of service on such tour at a rate equal to 25 percent of such employee’s hourly rate of basic pay.

((c)) The Secretary shall prescribe by regulation standards for compensation and payment under this section.