(a) The Board will allocate a portion of the TSP's administrative expenses to mutual fund users by charging an administrative fee of $55.00 annually. The amount of this fee will be redetermined once every three years by multiplying the average mutual fund window account balance by the TSP administrative expense ratio, as of the date of redetermination.(b) The fee described in paragraph (a) of this section is in addition to any mutual fund window account maintenance fees, trading fees, and fees and expenses associated with the specific mutual fund(s) in which the participant chooses to invest.