Prior to any negotiation or call for bids for any public works contract or any other contract covered by this chapter, the estimated amount of which exceeds twenty-five thousand dollars, the head of the county department involved shall prepare or cause to be prepared a detailed estimate of the amount of such contract. No contract for the construction of any public work shall be awarded on a bid exceeding the estimate by more than ten percent without supporting justification and the approval of the council on written motion. No other contract covered by this chapter shall be awarded on a bid which exceeds the estimate by more than ten thousand dollars without the approval of the council. (Added by Ord. 83-018 § 1, Apr. 7, 1983; Amended by Ord. 80-110 § 2, Jan. 20, 1981; Amended by Ord. 86-003 § 20, Feb. 12, 1986; Amended by Ord. 92-085, Aug. 12, 1992; Amended by Emerg. Ord. 12-073, Aug. 27, 2012, Eff date Aug. 27, 2012).