A person who was born on or after April 2, 1932 and who was a class 4 insured person on March 31, 2002, and who, on April 1 of that year, is employed at an applicable place of business, acquires on that day status as an insured under Article 9 of the Employees' Pension Insurance Act as amended by Article 5, and loses status as that class 4 insured person.