In making the classification provided for in §69-5-305, the commissioners are authorized to divide the land of one (1) owner lying in one (1) body into more than one (1) tract, and classify each subdivision of the tract, if they are of opinion that portions of the entire tract will be more benefited than other portions, and especially when the entire tract is a large one, and that it will be more equitable and just to so classify it in subdivisions.