Using a Dynamically Generated Texture to Send Data to a Shader

I'm trying to build a shader that will read the red channel values of a texture to use as an index. However, the color values I set in the data texture aren't the same values the shader reads when sampling the data texture.

For example, I build a data texture dynamically and set every pixel to Color32(15, 15, 15, 15) using setPixels32 (when I create the new Texture2D I set filter to point, wrap to clamp, disable mipmaps, and set linear to true).

Then when I sample the texture in the shader using tex2D, I would expect to get a float4 with values around 0.059 (~15/255) for x, y, z, and w.

However, I don't get the values I set, and the x,y,z, and w values are all different.

Is the problem something to do with going between linear and gamma color spaces?

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I'm using this to generate a tile map Similar to this http://www.dfworkshop.net/improved-terrain-tiling/

The difference is that I'm using a dynamically generated index texture.

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Edit:

Specific example. I set every pixel to Color32(1,1,1,1) and then when I sample a pixel of the texture in the shader I get the following value (examined with the VS graphical debugger).

x = 0.266666700, y = 0.537254900, z = 0.101960800, w = 1.000000000