A person whose service in a position as a management official began prior to November 10, 1978, and who was not immediately prior to November 10, 1978, in violation of section
19 of title
15 is not prohibited by section
3202 or section
3203 of this title from continuing to serve in that position. The appropriate Federal depository institutions regulatory agency may provide a reasonable period of time for compliance with this chapter, not exceeding fifteen months, after any change in circumstances which makes service described in the preceding sentence prohibited by this chapter, except that a merger, acquisition, increase in total assets, establishment of one or more offices, or change in management responsibilities shall not constitute changes in circumstances which would make such service prohibited by section
3202 or section
3203 of this title.