Nope, when you bake an object, it's supposed to be all one smoothing group, which will produce a lot of gradients. But this is different for everything, for example, if you were baking a normal for udk, the smoothing groups should correspond to the uv islands.
Maybe you can get a better understanding of what the normal map is doing for you if you applied a real time shader with the normal map, so you don't have to render to see the result. Use a directX material, and apply a shader that uses normal maps. I like xoliul's shader:…
You're supposed to have any 'outside' beveled model, anything which is 'outside' the silhouette and is changing it be modeled, especially on that Box, a bevel like that wont' show too well on a Normal Map. It's simply too strong, something less and subtle will show up better in information baking. On the other hand,…