CG shader tile issue

Hi, im developing a shader that blends two textures taking into account only the alpha of texture 1. This seems to work fine, but if i want to set diferent tiling or scale for each texture only tile on the 1st one is taken into consideration. This is my code:

 Shader "My Shaders/Unlit/Mixer Alpha Blend" {
     
 Properties {
     _Blend ("Blend", Range (0,1)) = 0.0 
     _MainTex ("Texture (A = Transparency)", 2D) = ""
     _BlendTexture ("BlendTexture (A = Transparency)", 2D) = ""
     _Cutoff ("Alpha Cutoff", Float) = 0.5
     
 } 
 
 SubShader {
     Tags {"Queue"="transparent" "RenderType"="transparent" }
     ZWrite Off
     Blend SrcAlpha OneMinusSrcAlpha
      Lighting Off
     
      
      Pass { 
     CGPROGRAM
     #pragma vertex vert
     #pragma fragment frag
 
     #include "UnityCG.cginc"
        
         sampler2D _MainTex;
            sampler2D _BlendTexture;
            uniform float _Cutoff;
            uniform float _Blend;
            
            
            
            float4 _MainTex_ST;
            float4 _BlendTexture_ST;
            
            struct v2f {
     float4  pos : SV_POSITION;
     float2  uv : TEXCOORD0;
 };
 
            
        v2f vert (appdata_base v){
     v2f o;
     o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
     o.uv = TRANSFORM_TEX (v.texcoord, _MainTex);
     
     return o;
 }
 
            
            
            half4 frag (v2f i) : COLOR{
            
            float4 MyColor = tex2D (_BlendTexture, i.uv).rgba;
            float4 MyAlpha = tex2D (_MainTex, i.uv).rgba;
            
            if (MyAlpha.a < _Cutoff)
                // alpha value less than user-specified threshold?
             {
                discard; // yes: discard this fragment
             }
       return lerp(MyAlpha, MyColor , _Blend);
      
     
             }
             
        
         ENDCG
         }
       
 }
 
 }