Mo. Rev. Stat. § 67.459
The portion of the cost of any improvement to be assessed against the real property in a neighborhood improvement district shall be apportioned against such property in accordance with the benefits accruing thereto by reasons of such improvement. The cost may be assessed equally per front foot or per square foot against property within the district or by any other reasonable assessment plan determined by the governing body of the city or county which results in imposing substantially equal burdens or share of the cost upon property similarly benefitted and which may include, in the case of condominium or equitable owner association ownership, a determination that all units within the condominium or equitable owner association are equally benefitted. The governing body of the city or county may from time to time determine and establish by ordinance or resolution reasonable general classifications and formulae for the methods of assessing the benefits.
§ 67.459, RSMo