7-12-4325. Incidental expenses considered as costs of improvements. The cost and expense connected with and incidental to the formation of the district, including the cost of preparation of plans, specifications, maps, and plats; engineering, superintendence, and inspection, including the compensation of the city engineer for work done; the cost of printing and advertising as provided in this part; and the preparation of assessment rolls must be considered a part of the cost and expenses of making the improvements within the special improvement district.