SpriteRenderer.SetPropertyBlock has no effect

Hi, I am using Unity 5.5.1

I have a custom shader, it's created from Sprite/Default, and I added 2 properties, like this

Code (csharp):

1.  
2.     Properties
3.     {
4.         [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
5.         _Color ("Tint", Color) = (1,1,1,1)
6.         [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
7.         [PerRendererData] _ActorY ("ActorY", Float) = 0             // My own data
8.         [PerRendererData] _ActorZ ("ActorZ", Float) = 0             // My own data
9.     }
10.  

And I set these 2 properties in my script:

Code (csharp):

1.  
2. SpriteRenderer SR;
3. MaterialPropertyBlock matProBlock = null;
4. void Update()
5. {
6.         if (matProBlock == null)
7.             matProBlock = new MaterialPropertyBlock();
8.  
9.         SR.GetPropertyBlock(matProBlock);
10.         matProBlock.SetFloat("_ActorY", trans.position.y);
11.         matProBlock.SetFloat("_ActorZ", m_zHeight);
12.         SR.SetPropertyBlock(matProBlock);
13. }
14.  

The problem is:
_ActorY and _ActorZ are always 0 when I get them in shader.

If I just use this code, everything is fine.

Code (csharp):

1.  
2. void Update()
3. {
4.     SR.material.SetFloat("_ActorY", trans.position.y);
5.     SR.material.SetFloat("_ActorZ", m_zHeight);
6. }
7.  

So, does SpriteRender eat my properties?

 

I already know why, I didn't call SetPropertyBlock

Code (csharp):

1.  
2. SR.SetPropertyBlock(matProBlock);
3.  

But I also figure out that if SetPropertyBlock is called for every sprite, then these sprites will not be batched together.
The way to use MaterialPropertyBlock and also enable batching is:
Pass _ActorY and _ActorZ through _Color, or vertex, or UV2, UV3..etc.