Blend 8 textures pixel shader

I was asked to post the source. It's set up to work within fx composer:

#define LIGHT_COORDS "World"
//-----------------
// un-tweaks
//-----------------
matrix WorldVP:WorldViewProjection;
matrix World:World; 

//-----------------
// tweaks
//-----------------
float3 LightPosition : POSITION <
string Object = "PointLight0";
string UIName = "Lamp 0 Position";
string Space = (LIGHT_COORDS);
> = {150.0f, 150.0f, 0.0f};

float4 LightColor : COLOR <
string UIName = "Lamp 0";
string Object = "Pointlight0";
string UIWidget = "Color";
> = {1.0f, 1.0f, 1.0f, 1.0f};

float LightRange <
string UIWidget = "slider";
float UIMin = 10.0;
float UIMax = 1000.0;
float UIStep = 5.0;
string UIName = "LightRange";
> = 250.0f; 

float4 Ambient <
string UIName = "Ambient";
string UIWidget = "Color";
> = {0.1f, 0.1f, 0.1f, 1.0f}; 

float BlendTexUScale<
string UIWidget = "slider";
float UIMin = 0.0;
float UIMax = 10.0;
float UIStep = 0.01;
string UIName = "BlendTexUScale";
> = 1.0f;

float BlendTexVScale<
string UIWidget = "slider";
float UIMin = 0.0;
float UIMax = 10.0;
float UIStep = 0.01;
string UIName = "BlendTexVScale";
> = 1.0f;

float waver<
string UIWidget = "slider";
float UIMin = 0.0;
float UIMax = 10.0;
float UIStep = 0.01;
> = 1.0f;


//-----------------
// Textures
//-----------------
texture tex1n; 
sampler2D tex1 = sampler_state{texture = ;};

texture tex2n; 
sampler2D tex2 = sampler_state{texture = ;};

texture tex3n; 
sampler2D tex3 = sampler_state{texture = ;};

texture tex4n; 
sampler2D tex4 = sampler_state{texture = ;};

texture tex5n; 
sampler2D tex5 = sampler_state{texture = ;};

texture tex6n; 
sampler2D tex6 = sampler_state{texture = ;};

texture tex7n; 
sampler2D tex7 = sampler_state{texture = ;};

texture tex8n; 
sampler2D tex8 = sampler_state{texture = ;};

texture texBlendn; 
sampler2D texBlend = sampler_state{texture = ;};

texture texBlend2n; 
sampler2D texBlend2 = sampler_state{texture = ;};

//-----------------
// structs
//-----------------
struct input
{
float4 Pos:POSITION;
float2 UV:TEXCOORD;
float3 Normal : NORMAL;
};
struct output
{
float4 OPos:POSITION;
float2 Tex:TEXCOORD0; 
float3 Attenuation:TEXCOORD1;
float Diffuse:TEXCOORD2;
};

//-----------------
// vertex shader
//-----------------
output VS(input IN)
{
output OUT;
OUT.OPos=mul(IN.Pos,WorldVP);
OUT.Tex=IN.UV;
float3 Wnor=mul(IN.Normal,World); Wnor=normalize(Wnor);
float3 WPos=mul(IN.Pos,World); 
float3 LightPos=LightPosition-WPos;
OUT.Attenuation=-LightPos/LightRange;
OUT.Diffuse=saturate(0.02f+mul(Wnor,LightPos)*0.02f);
return OUT;
}

//-----------------
// pixel shader
//-----------------
float4 PS(output IN) : COLOR
{
IN.Tex += float2(IN.Tex.x,sin(IN.Tex.x*waver));
float4 Texture1=tex2D(tex1,IN.Tex);
float4 Texture2=tex2D(tex2,IN.Tex);
float4 Texture3=tex2D(tex3,IN.Tex);
float4 Texture4=tex2D(tex4,IN.Tex);

float4 Texture5=tex2D(tex5,IN.Tex);
float4 Texture6=tex2D(tex6,IN.Tex);
float4 Texture7=tex2D(tex7,IN.Tex);
float4 Texture8=tex2D(tex8,IN.Tex);

float4 tBlend=tex2D(texBlend,IN.Tex*float2(BlendTexUScale,BlendTexVScale));
float4 tBlend2=tex2D(texBlend2,IN.Tex*float2(BlendTexUScale,BlendTexVScale));

float4 DiffuseLight=1-saturate(dot(IN.Attenuation,IN.Attenuation));
float4 Light=DiffuseLight*LightColor*IN.Diffuse;

return (tBlend.x*Texture1 +
tBlend.y*Texture2 +
tBlend.z*Texture3 +
tBlend.w*Texture4 +

tBlend2.x*Texture5 +
tBlend2.y*Texture6 +
tBlend2.z*Texture7 +
tBlend2.w*Texture8 )*(Light+Ambient);
}

//-----------------
// techniques 
//-----------------
technique CubicLighting
{
pass p1
{ 
vertexShader = compile vs_1_0 VS();
pixelShader = compile ps_2_0 PS(); 
}
}