For the purposes of this subsection, the period of obligated service for a recipient of financial assistance under this section shall be the period determined by the Secretary as being appropriate to obtain adequate service in exchange for the financial assistance and otherwise to achieve the goals set forth in
section 7901(a) of this title. In no event may the period of service required of a recipient be less than the period equal to the total period of pursuit of a degree for which the Secretary agrees to provide the recipient with financial assistance under this section. The period of obligated service is in addition to any other period for which the recipient is obligated to serve on active duty or in the civil service, as the case may be.