ASML is the world’s leading provider of lithography systems for the semiconductor industry, manufacturing complex machines that are critical to the production of integrated circuits. Maintenance of ASML’s installed base is performed by the Customer Support (CS) organization and Field Factory (FF) is a growing division in CS that is responsible for performing upgrades, installs and relocations in the field. FF DUV/YS Upgrades department is interested in analyzing new possibilities for short-term planning. To achieve this, a tool for scenario analysis is needed. For the construction of a mathematical tool, a first step is the study of the mathematical complexity of the problem.