A data warehouse is usually modeled using a multidimensional view of data. A multidimensional model has dimensions composed of levels hierarchically organized according to their full containment. For example, in a geographical dimension with Department and Country levels, a department is fully contained in a country. Recently, a generalization of full containment has been proposed. It is known as the partial containment. For example, only 0.2 (20%) of a highway could be contained in a department. In this paper we adopt a multidimensional model that supports partial containment and extend this model in order to support the change of the degree (percentage) of containment, because this degree can change over time. Our extension is also incorporated into a multidimensional query language, which enables what-if analysis. In order to illustrate the expediency of our proposal, we present a case study related to car accidents.