Section 27A. Within five days from the date of the first advertisement or call for bids, two or more employers of labor, or two or more members of a labor organization, or the awarding officer or official, or five or more residents of the town or towns where the public works are to be constructed, may appeal to the commissioner or his designee from a wage determination, or a classification of employment as made by the commissioner, by serving on the commissioner a written notice to that effect. Thereupon the commissioner or his designee shall immediately hold a public hearing on the action appealed from. The commissioner or his designee shall render his decision not later than three days after the closing of the hearing. The decision of the commissioner or his designee shall be final and notice thereof shall be given forthwith to the awarding official or public body.