Adding a new feature isn't just about coding or designing it. It's about integrating it into everything else. A new button might break the mobile layout, require new backend logic, and trigger 3 new bugs. The larger your original project, the higher the integration penalty (Complexity Tax) for every new addition.

We calculate the "Raw Days" (e.g., 4 small features = 4 days). Then we apply a non-linear multiplier based on the size of the base project and the volume of changes. A project expanding by 30% generates a much higher bug-rate and testing overhead than a project expanding by 5%. This hidden overhead is the true killer of budgets.