The report documents modifications to the state level model portion of the Advanced Utility Simulation Model (AUSM), one of four stationary source emission and control cost forecasting models developed for the National Acid Precipitation Assessment Program (NAPAP). The AUSM model, originally developed in two principal parts (the national loop and the state level model), projects air pollution control, and electric rates by consumer category by state and year. The state level model modifications followed testing and review that identified four types of required revisions: (1) correction of coding errors which caused syntactical or logical problems; (2) addition of new knowledge about electric utility operations, generating and emissions control equipment, ways in which users wish to run the model, and user information needs; (3) modification of components to permit calibration of AUSM to more accurately simulate the historical years, 1980-1985; and (4) incorporation of changes in external factors such as new tax requirements and financing trends. Only Revisions 2, 3, and 4 are included in the volume. Revision 1 modifications are documented in the source code by comment.