The department shall establish schedules for repayment of the principal and interest on any financial assistance made under the provisions of sections 335.212 to 335.242. Interest at the rate of nine and one-half percent per annum shall be charged on all financial assistance made under the provisions of sections 335.212 to 335.242, but the interest and principal of the total financial assistance granted to a qualified applicant at the time of the successful completion of a nursing degree, diploma program or a practical nursing program shall be forgiven through qualified employment.