This ability to reduce total quality costs dramatically in all categories is borne out by real-world experiences. Tennant, for example, over an eight-year period, reduced its costs of quality from 17 percent of sales to 2.5 percent of sales and, at the same time, significantly altered the relative distribution of the quality cost categories. At the very beginning, failure costs accounted for 50 percent of the total costs of quality (8.5 percent of sales) and control costs of 50 percent (8.5 percent of sales). When the 2.5 percent level was achieved, failure costs accounted for only 15 percent of the total costs of quality (0.375 percent of sales), and control costs had increased to 85 of the total (2.125 percent of sales). Tennant increased quality, reduced quality costs in every category and in total, and shifted the distribution of quality costs to the control categories, with the greatest emphasis on prevention. This outcome argues strongly against the traditional quality cost model portrayed in Exhibit 15-5. According to this model, total quality costs can be decreased only by trading off control and failure costs (increasing one while decreasing the other). Further support for the total quality control model is provided by Westinghouse Electric. Similar to Tennant, Westinghouse Electric found that its profits continued to improve until its control costs accounted for about 70 to 80 percent of total quality cost. Based on these two companies' experiences, we know that it is possible to reduce total quality costs significantly-in all categories-and that the process radically alters the relative distribution of the quality cost categories.