, Graff Chevrolet, Rankin, Superior Coach of Florida v. Commissioner, 80 T.C. 895, 912 (1983), Weiss v. Commissioner, 395 F.2d 500 (10th Cir. 1968), Spang Industries, Inc. v. United States, 6 Cl. Ct. 38, 46 (1984), rev'd on other grounds 791 F.2d 906 (Fed. Cir. 1986). Whether Field Operations' adjustment constitutes a