When a performance bond is required by state law or otherwise by the call for bids, the successful bidder shall furnish a duly executed bond upon a form furnished by the county, signed by an approved surety or sureties in the full amount of the contract price conditioned as required therein and by RCW 39.08.010 as now or hereafter amended and any other applicable state law; PROVIDED, That in lieu of a performance bond on any contracts of $3,500 or less the manager, in his discretion, may retain 100 percent of the contract amount for a period of 30 days after the date of final acceptance, or until receipt of all necessary releases from the Department of Revenue and the Department of Labor and Industries, whichever is later. Upon receipt of an executed performance bond, the division shall file it with the director of the department of finance. In projects where a performance bond is not required by state law, the county executive may still require such bond when he concludes that such is required in the best interests of the county. Any question with respect to the adequacy of any bond shall be determined by the manager. (Added by Ord. 80-110 § 2, Jan. 20, 1981; Amended by Ord. 86-003 § 18, Feb. 12, 1986; Amended by Ord. 89-027 § 17, May 17, 1989).