Designing a product line architecture can be approached from scratch or by deducing it after having built a series of similar products. We hereby present a different approach where we designed a product line architecture after only one product was built. Given MCC+, a product for consistency checking of different diagrams in a UML model, we identified the variabilities it should manage in order to be useful for a variety of modeling tools, obtaining a product line MCC-SPL. We accordingly upgraded the original architecture to a product line architecture (PLA). We verified how well the proposed PLA generalizes the single product architecture using a simple yet well known product line architecture assessment method. We also validated the usefulness of the just designed PLA by porting the tool to a different modeling platform.