Every electrical utility must furnish the Office of Regulatory Staff in such form and in such detail as the Office of Regulatory Staff requires, subject to the approval of the commission, all tabulations, computations, and other information required by the Office of Regulatory Staff to carry into effect any of the provisions of this chapter and must make special answer to all questions submitted by the Office of Regulatory Staff. Each electrical utility receiving from the Office of Regulatory Staff any blanks with directions to fill out must cause the blanks to be properly filled out so as to answer fully and correctly each question propounded therein and it shall return the tabulations, computations, and other information to the Office of Regulatory Staff within the time required. But in case any electrical utility is unable to answer any question, it must so state with good and sufficient reasons therefor. When required by the Office of Regulatory Staff, each electrical utility must deliver to the Office of Regulatory Staff copies of any or all maps, profiles, contracts, franchises, reports, books, accounts, papers, and records in its possession or in any way relating to its property or affecting its business and also a complete inventory of its property in the form as the Office of Regulatory Staff directs. Each electrical utility must, when required by the Office of Regulatory Staff, furnish in such form as the Office of Regulatory Staff requires all such reports as it may be directed by the Office of Regulatory Staff to furnish in relation to its operations, property, or business, and the Office of Regulatory Staff may require either periodical or special reports concerning any matter as to which it desires to inquire in order to keep itself informed in the performance of its duties under this chapter. All reports must be under oath by the officer or officers of the electrical utility as may be required by the Office of Regulatory Staff.