## 3 Discussion
### Findings for Each of the Nine Concepts  
Each product architecture choice targets a single production strategy: integral for MP, modular for MC, and open for MPa. The presence of product architecture across all strategies might indicate that it is a prerequisite to other concept choices.  
Each type of modular breakdown can be selected based on its specific advantages. The choice of modular breakdown does not appear to be determined by product variety. The choice of breakdown type might be influenced by the advantages of certain methods, notably product and systems complexity, the type of product architecture, and assembly complexity.  
Product platform definitions are adapted to different levels of variety. However, a set of standard modules can coexist with a set of rules, interfaces, and positions. The two definitions of platforms could complement each other and result in benefits from reduced production costs and product flexibility. The idea of having a product platform, defined as a set of stable modules could penalize cases of high variety by limiting product flexibility.  
Variety management, always aims at balancing customer satisfaction and reducing complexity. Variety management tools precisely target the objectives of MC and MPa, highlighting their importance from the presence of variety. The technical/functional variety seems to be more concrete and applicable due to its more precise level of abstraction.  
Interface management becomes more important with a significant change in product variety. Interchangeability becomes a priority when product complexity becomes unmanageable. To achieve effective interchangeability between modules, the modular strategy requires a more structured application and tighter management of interface control.  
Modular manufacturing tools primarily aim for mass production at low costs. To achieve this, the majority of these tools aim to increase production flexibility and agility to accommodate a wider variety while keeping costs low. These practices have little or no impact on product variety.  
Configuration is a concept whose tools allow for more efficient management of the sale of all this product variety. These tools are essential for collecting personalized needs and involving the customer in the design of individualized products.  
Certain modularity measurement groups appear to be more suited depending on the product variety level. However, most measurement groups seem to measure one of the first seven concepts presented. The associations of measurement groups with the following concepts could be studied more in depth:  
* Commonality and standardization with the product platform concept;
* Connectivity and interface with the interface management concept;
* Manufacturing costs with the modular manufacturing concept;
* Personalization and variety with the variety management concept.  
Complexity measures and complexity reduction methods become more relevant with the increase in product variety or in the presence of complexity. Static complexity is much more relevant in the context of modularity since design has a direct impact on internal variety and is closely linked to static complexity. These tools complement the preceding concepts.