Unexpected Draw Calls

I just started playing around with Unity5 and was wondering if someone could chime in on why I'm seeing unexpected draw call numbers in a simple test scene. If I place 4 cubes (no batching turned on) in an empty scene with a directional light I get 5 draw calls as expected (including 1 for the skybox). If I then enable shadowing on the light but turn off casting and receiving on all the cubes I jump up to 9 which is a little unexpected. If I move those cubes to a layer and set the culling mask on the light to not include that layer I still am at 9. I would expect both of these cases to still be at 5 draw calls. This is a little frightening once those 4 cubes become 100 cubes which are not even supposed to be affected by the light and my draw calls are doubled. This is all in forward rendering in case that matters.

No shadows:



Shadows turned on but cast/receive turned off on cubes and culling mask on light set to not include cubes:



Thanks for any insight,

Justin

 

Check this post to understand Batches and SetPass calls (that are replacing draw calls in Unity 5)
http://forum.unity3d.com/threads/render-statistics.284970/

And the documentation :

http://docs.unity3d.com/Manual/RenderingStatistics.html

In this case, it seems that adding shadows only add one SetPass call, which is good. Also, what rendering pipeline are you using? Deferred?