What is the test for pre-emption in the context of regulations by the Federal Trade Commission?

As the United States Supreme Court recently stated: "[B]ecause agencies normally address problems in a detailed manner and speak through a variety of means, including regulations, preambles, interpretive statements, and responses to comments, we can expect that they will make their intentions clear if they intend for their regulations to be exclusive. Thus, if an agency does not speak to the question of pre-emption, we will pause before saying that the mere volume and complexity of its regulations indicate that the agency did in fact intend to pre-empt." (Hillsborough County v. Automated Medical Labs. (1985) 471 U.S. 707, 718, 105 S.Ct. 2371, 2377, 85 L.Ed.2d 714.)