The commission shall make or cause to be made a complete list of the benefits and assessments setting forth, by legal description or street address or both, each lot or tract of land assessed, the amount each lot or tract is benefited by the improvement, and the amount assessed against each. There must be attached to the list of assessments a certificate signed by a majority of the members of the commission certifying that the same is a true and correct assessment of the property therein described to the best of their judgment and stating the several items of expense included in the assessment.