While away from their homes or regular places of business in the performance of services for the Task Force, Task Force members shall be allowed travel expenses, including a per diem allowance in lieu of subsistence, in the same manner as persons employed intermittently in the Government service are allowed travel expenses under section
5703 of title
5. Any Task Force member who is an employee of an agency or governmental unit and is eligible for travel expenses from that agency or unit for performing services for the Task Force is not eligible for travel expenses under this paragraph.