Activity-based costing (ABC) and Theory of Constraints (TOC) are popular managerial tools for evaluating product mix decisions. A challenging aspect of the product mix problem involves evaluating joint products. These products involve complex interactions among resources and products and sequential decisions concerning producing joint products and their further processing. ABC and TOC assume that managers either have complete control or have no control over labor and overhead resources. However, managers generally have varying degrees of control over these resources. The purpose of this paper is to develop a general ABC model that embeds management discretionary power over labor and overhead resources. The paper illustrates the general model leads to optimal joint product mix decisions when the ABC and the TOC may not.