In addition to the basic Work Authorization Letters originated by the Commission's Contracting Officer the Contractor's Project Manager issues various forms of work orders. These work orders may de described as follows: 1. Engineering Work Orders are issued by the Jobsite Engineering Manager to the Jobsite Construction Manager to proceed with work outlined, in accordance with approved plans and specifications. 2. Change Orders are initiated at the Jobsite to cover or meet practical field conditions, to meet changed requirements, or to achieve economy and efficiency. All Change Orders are subject to approval of beth the Contractor's Resident Manager and the Commission's Residemt Engineer, together with formal submittal of Cost Estimates to the Commission's Centracting Officer for review and approval as modifications to the Contract, if necessary . 3. Extraordinary Maintenance Work Orders are issued te cover unusual or large maintenance items which could not be anticipated in preparation of the original Job 4 Estimate. Here, likewise, formal estimates are gubmitted to the Commission for review and approval. 4. | Job-No. 5 Work Orders cover requests of "Users" for Contractor's services. These requests are approved by the Commission's Representative at the Jobsite. Samples showing the form of the various types of work orders are presented as exhibits at the end of this section. GENERAL ACCOUNTING AND COST ACCOUNTING The initial Charts of Accounts and the early financial and cost statements, reports, and records confermed to Contrect Appendix "D" and to other specific, written instructions of the AEC.~ These written instructions were furnished in detailed clarification and confirmation of oral instructions given toe the On-Continant Controller by representatives of the AEC Finance Division, at Los Alamos, on May 16 and 17, 1949. Except for minor revisions and additional reports required by the Com- mission in accordance with various directives in the form of Controller's Releases, GM Bulletins, SF Bulletins, and others, all fiscal records, statements, and reports were maintained and submitted in accordance with these instructions, through December 31, 1949. (aan te letters, May 18, 1949 (N-747 and -748); ABC letter, undated “controller's Trip Report, May 18, 1949. 11-14