Appointed members of the Board who are not employees of the Federal Government, while attending meetings or conferences of the Board or otherwise serving on business of the Board, shall be entitled to receive compensation at rates fixed by the President, but not exceeding $100 per day, including travel time, and while so serving away from their homes or regular places of business they may be allowed travel expenses, including per diem in lieu of subsistence, as authorized by
section 5703 of title 5 for persons in the Government service employed intermittently.