The ability of companies to rapidly conduct a changeover from one product to another as part of a production process is a fundamental step towards a more flexible production system that can deal with an increasingly dynamic and competitive market. Single-Minute Exchange of Die (SMED) is the best-known lean tool that aims to reduce time consumption in the changeover process. This paper presents a new Lean tool called Set-up Saving Deployment (SSD), which improves set-up efficiency by classifying, analyzing, and removing set-up losses within a changeover process, and which supports decision-making for SMED implementation. SSD uses three matrices, constructed sequentially from the first (L-Matrix) to the last (ECE-Matrix), in order to assess the possible time savings that can be achieved by eliminating losses and, in addition, to forecast possible improvements resulting from implementing a SMED project. SSD also provides a new basket of tailored set-up efficiency indicators that allow the analysis team to correctly assess set-up efficiency, and compare the 'as is' condition with the subsequent 'to be' condition from an operational perspective. The effectiveness of SSD in addressing set-up losses and predicting time savings is illustrated using an industrial case study of a resin doming machine. Thanks to its structured step-by-step procedure, SSD significantly improves the efficiency of the changeover process.