Edges shaded smooth in Unity when they should be flat

Hi, I have an issue with flat shaded surfaces and edges being shaded smooth when imported into Unity. In 3DSMax and Blender, there is no issue everything is shaded flat as shown below, which is what I intend:

However, when I import it into Unity:

You can see that the top part of the side legs are smooth shaded when they shouldn't be.

Solutions I have tried: 1.) Recalculating normals in Unity import settings and setting the smoothing angle to zero 2.) Adding an edge split modifier in external 3D app

...still with the same results.

Any possible ideas why this is happening and solutions? Thanks in advanced!