No state employee shall be compensated for services rendered to more than one state agency during a biweekly pay period unless the appointing authority of each agency or such authority’s designee certifies that the duties performed are outside the responsibility of the agency of principal employment, that the hours worked at each agency are documented and reviewed to preclude duplicate payment and that no conflicts of interest exist between services performed. No state employee who holds multiple job assignments within the same state agency shall be compensated for services rendered to such agency during a biweekly pay period unless the appointing authority of such agency or his designee certifies that the duties performed are not in conflict with the employee’s primary responsibility to the agency, that the hours worked on each assignment are documented and reviewed to preclude duplicate payment, and that there is no conflict of interest between the services performed. Any dual employment arrangement that results in the necessity to pay overtime shall be approved in advance by the Commissioner of Administrative Services.