Falloff map not smoothing edge of terrain

Question

I have a procedurally generated terrain where I am looking to smooth the edges of the terrain using a falloff map so the edges do not abruptly cut off. The falloff map applies itself but it does not seem to smooth out the edge of the terrain and I cannot seem to figure out why. Would appreciate any insight into what might be causing this.

Full script with falloff applied TerrainGeneration.cs

Falloff map generation

float[] FallOff() {

float[] falloffmap = new float[(Width + 1) * (Depth + 1)];

int n = 0;
for(int h = 0; h < Depth; h++)
{
    for(int w = 0; w < Width; w++) {

        float x = w / (float)Width * 2 - 1;
        float y = h / (float)Depth * 2 - 1;

        float value = Mathf.Max(Mathf.Abs(x), Mathf.Abs(y));
        falloffmap[n] = EvaluateFallOff(value);
        n++;
    }
}
return falloffmap;
}

Applying the falloff

public void CreateMesh()
{

vertices = new Vector3[(Width + 1) * (Depth + 1)];
noiseArray = PerlinNoise();

int i = 0;
for(int z = 0; z <= Depth; z++)
{
    for(int x = 0; x <= Width; x++)
    {
        noiseArray[i] = Mathf.Clamp01(noiseArray[i] - falloffmap[i]);
        var currentHeight = noiseArray[i];

        if(currentHeight > HeightThreshold)
        {
            currentHeight = heightCurve.Evaluate(currentHeight) * HeightMultiplier;
        }

        vertices[i] = new Vector3(x, currentHeight, z);
        i++;
    }
}

Output I am getting with the applied falloff map

The falloff map