WrightWay Co. is implementing a standard cost system. One of the system-design choices that WrightWay management must make is choice of the denominator volume level for calculating the fixed overhead application rate, which is used to determine product costs. Various alternatives exist for the denominator volume. What provisions of generally accepted accounting principles (GAAP) and current income tax requirements in the U.S. affect the decision as to choice of the denominator volume level when developing the standard fixed overhead application rate? Provide an overview of the requirements in this regard.