Does Unitys built-in Sprites dynamic batching work differently and add more draw calls then needed?

Hi All,

I've put together a performance simple test using Unitys built-in 2D support. I have an ortho camera, a sprite prefab and some logic that spawns more and more of the same prefab which I click on the screen, the sprites then just bounce and rotate around the screen. The sprite prefab is nothing fancy, I'm using the built-in default sprite material / renderer etc.

Sprites instances are dynamically batching but around every 700 Tris / 1400 Verts added from new sprite instances another drawcall is added. Is this intended behavior as running a similar test using other 3rd Party 2D frameworks like 2D Toolkit & Futile I drawcalls stay the same even at the higher amounts of sprites?

I've looked here http://docs.unity3d.com/Manual/DrawCallBatching.html but can't see anything that applies particularity as batching is occurring just not how I thought it would at higher amounts of sprites.

Maybe I'm doing something wrong but its about as simple as it can be. Any help or education is appreciated!

Pete