When the improvement security provided pursuant to Section 16.20.170 is a surety bond, it shall be accompanied by a bond for the security of laborers and materials in an amount not less than fifty percent of the estimated cost of the improvements. When the improvement security is a cash deposit or instrument of credit, such security shall include an additional amount necessary for the protection of laborers and materials but in no event less than fifty percent of the estimated cost of the improvements. Security for one hundred percent of the estimated costs, including a factor for inflationary cost increases, may be required. (Ord. 1729 § 4 (Exh. A), 2023)