so accepted, a pro rata reduction shall be made in any entitlement of the employee to payment from the Government for such expenses. (b) Prohibiting acceptance from other sources Except as provided in this section or section 7342 of title 5, United States Code, the Office or an employee of the Office may not accept payment for expenses referred to in subsection (a). An employee who accepts any payment in violation of the preceding sentence— (1) may be required, in addition to any penalty provided by law, to repay, for deposit in the general fund of the Treasury, an amount equal to the amount of the payment so accepted