In determining when an action is commenced for the purposes of section
255 of this title, an action commenced on or after May 14, 1947 under the Fair Labor Standards Act of 1938, as amended [
29 U.S.C.
201 et seq.], the Walsh-Healey Act [
41 U.S.C.
35 et seq.], or the Bacon-Davis Act, shall be considered to be commenced on the date when the complaint is filed; except that in the case of a collective or class action instituted under the Fair Labor Standards Act of 1938, as amended, or the Bacon-Davis Act, it shall be considered to be commenced in the case of any individual claimant—