1. A method of performing activity based cost modeling wherein an activity cost is allocated to a cost array having a plurality of cost objects, the steps for each of the plurality of cost objects comprising: retrieving a selected plurality of allocation weights each from a corresponding one of a plurality of weight arrays, the activity cost being allocated by at least one facet, each of the at least one facet having a plurality of categories, each of the selected plurality of allocation weights corresponding to one of the plurality of categories of one of the at least one facet; retrieving a selected cost driver from a cost driver array, the selected plurality of allocation weights and the selected cost driver corresponding to one of the plurality of cost objects; calculating a weighted allocation factor based on the selected cost driver and the selected plurality of allocation weights; and assigning an allocated activity cost to the respective cost object by multiplying the activity cost and the weighted allocation factor.