Abstract Manufacturing industry is facing new challenges in a competitive and constantly changing environment, with growing complexity and high levels of customization. Mass customization caused that product variety increased drastically and affects production system flexibility. System flexibility is the ability of the system to cope with product variety. Based on industrial experience, the production system may be represented by three main elements, which are products, processes and resources. This paper, which is a part of an overall research work, studies the products - processes interaction. This interaction investigates the ability of the processes to manage existing and potential product variety. Based on a set of constraints, which are used to build sequences, an indicator is introduced to provide decision support capabilities to guide the changes to perform in the production system for better sequence flexibility. Experimental results from the automotive industry are presented.