An individual who is a career appointee in the Senior Executive Service receiving basic pay at one of the rates payable under
section 5382 of title 5 and who accepts a limited appointment in the Senior Foreign Service in a salary class for which the basic salary rate is less than such basic rate of pay, shall be paid a salary at his or her former basic rate of pay (with adjustments as provided in paragraph (2)) until the salary for his or her salary class in the Senior Foreign Service equals or exceeds the salary payable to such individual under this subsection.