Unity 5 shader error : Too many texture interpolators would be used for ForwardBase pass (11 out of max 10)

Hi,

I'm trying to use good old T4M shader in Unity 5 and it seems there is an extra interpolator in action. Is there a way to still use it without setting it to shader target 4.0?

 Shader "T4MShaders/ShaderModel2/Diffuse/T4M 4 Textures" {
 Properties {
     _Splat0 ("Layer 1", 2D) = "w$$anonymous$$te" {}
     _Splat1 ("Layer 2", 2D) = "w$$anonymous$$te" {}
     _Splat2 ("Layer 3", 2D) = "w$$anonymous$$te" {}
     _Splat3 ("Layer 4", 2D) = "w$$anonymous$$te" {}
     _Control ("Control (RGBA)", 2D) = "w$$anonymous$$te" {}
     _MainTex ("Never Used", 2D) = "w$$anonymous$$te" {}
 }
                 
 SubShader {
     Tags {
    "SplatCount" = "4"
    "RenderType" = "Opaque"
     }
 CGPROGRAM
 #pragma surface surf Lambert 
 #pragma exclude_renderers xbox360 ps3
 #pragma target 3.0
 
 struct Input{
     float2 uv_Control : TEXCOORD0;
     float2 uv_Splat0 : TEXCOORD1;
     float2 uv_Splat1 : TEXCOORD2;
     float2 uv_Splat2 : TEXCOORD3;
     float2 uv_Splat3 : TEXCOORD4;
 };
  
 sampler2D _Control;
 sampler2D _Splat0,_Splat1,_Splat2,_Splat3;
  
 void surf (Input IN, inout SurfaceOutput o) {
 
     fixed4 splat_control = tex2D (_Control, IN.uv_Control).rgba;
         
     fixed3 lay1 = tex2D (_Splat0, IN.uv_Splat0);    
     fixed3 lay1_2 = tex2D (_Splat0, IN.uv_Splat0 * -0.015);
     
     fixed3 lay2 = tex2D (_Splat1, IN.uv_Splat1);
     fixed3 lay2_2 = tex2D (_Splat1, IN.uv_Splat1 * -0.015);
     
     fixed3 lay3 = tex2D (_Splat2, IN.uv_Splat2);
     fixed3 lay3_2 = tex2D (_Splat2, IN.uv_Splat2 * -0.015);
     
     fixed3 lay4 = tex2D (_Splat3, IN.uv_Splat3);
     fixed3 lay4_2 = tex2D (_Splat3, IN.uv_Splat3 * -0.015);
     
     o.Alpha = 0.0;
     o.Albedo.rgb = (((lay1 * splat_control.r / 2) + (lay1_2 * splat_control.r / 2)) + 
                     
                     ((lay2 * splat_control.g / 2) + (lay2_2 * splat_control.g / 2)) + 
                     
                     ((lay3 * splat_control.b / 2) + (lay3_2 * splat_control.b / 2)) + 
                     
                     ((lay4 * splat_control.a / 2) + (lay4_2 * splat_control.a / 2)));
 }
 ENDCG 
 }
 // Fallback to Diffuse
 Fallback "Diffuse"
 }