Bidders are also required to examine all maps, plans, and data mentioned in the specifications, contract or proposal as being on file in the office of the Chief Engineer, for examination by bidders. No plea of ignorance of conditions that exist or that may hereafter exist or of conditions or difficulties that may be encountered in the execution of the work under this contract, as the result of a failure to make the necessary examinations and investigations, will be accepted as an excuse for any failure or omission on the part of the Contractor to fulfill in every detail all of the requirements of said contract, specifications and plans, or will be accepted as a basis for any claims whatsoever for extra compensation. Upon application all information in the possession of the Chief Engineer will be shown to bidders, but the correctness of such information will not be guaranteed by the Sanitary District. The following schedule of quantities, although stated with as much accuracy as is possible in advance, is approximate only, and is assumed solely for the purpose of comparing bids. Then follows an itemized schedule of the quantity of work to be done after which comes the following: Bidders must determine for themselves the quantities of work that will be required, by such means as they may prefer, and shall assume all risks as to variations in the quantities of the different classes of work actually furnished under the contract. Bidders shall not at any time after the submission of this proposal, dispute or complain of the aforesaid schedules of quantities or assert that there was any misunderstanding in regard to the amount or the character of the work to be done, and shall not make any claims for damages or for loss of profits because of a difference between the quantities of the various classes of work assumed for comparison of bids and the quantities of work actually performed. Proposals that contain any omissions, erasures, or alterations, conditions or items not called for in the contract and plans attached hereto, or that contain irregularities of any kind, will be rejected as informal. Bids manifestly unbalanced will not be considered in awarding the contract.[76] No bid will be accepted unless the party making it shall furnish evidence satisfactory to the Board of Trustees of the Sanitary District of Chicago of his experience and familiarity with work of the character specified and of his financial ability to successfully and properly prosecute the proposed work to completion within the specified time.