Texture wont scroll on y-axis.

I've been playing around with shaders for about a week now and I've tried to make a shader that scrolls textures.It works but only on the x axis.Heres the code.

 Shader "LearningShaders/Chapter2/ScrollingTextures" {
     Properties {
         _MainTex("Base (RGB)", 2D) = "white" {}
         _MainTint("DiffuseTint",Color)=(1,1,1,1)
         _ScrollXSpeed("xspeed",Range(0,10))=2
         _ScrollYSpeed("yspeed",Range(0,10))=2
     }
     SubShader {
         Tags { "RenderType"="Opaque" }
         LOD 200
         
         CGPROGRAM
         #pragma surface surf Lambert
 
         sampler2D _MainTex;
         fixed4 _MainTint;
         fixed _ScrollXSpeed;
         fixed _ScrollYSpeed;
         
 
         struct Input {
             float2 uv_MainTex;
         };
 
         void surf (Input IN, inout SurfaceOutput o) {
         fixed2 scrolledUV = IN.uv_MainTex;
         
         fixed xScrollValue = _ScrollXSpeed*_Time;
         fixed yScrollValue = _ScrollYSpeed*_Time;
         
         scrolledUV += fixed2(xScrollValue,yScrollValue);
         
         
             half4 c = tex2D (_MainTex, scrolledUV);
             o.Albedo = c.rgb*_MainTint;
             o.Alpha = c.a;
         }
         ENDCG
     } 
     FallBack "Diffuse"
 }

Thanks in advance.