Render Stats, Used Textures and VRAM Usage

Unity 2.5.1

I can't fathom the reporting of Used Textures in the Render Statistics menu.

I have 12 planes in the viewport each displaying a different 256x512Mb texture.(The textures are actually 256x422 RGB DXT1 compressed to 70.8kb each).

The Render Sats window correctly reports:
Used Textures: 12 - 8.0 MB
(Height 256 * Width 512* ColDepth 32 * MipMaps 1.333 * Num Textures 12) / 8388608 = 8 MB

(By the way I have noticed that if I change the Max texture size and don't build the project - thereby compressing the textures, the render stats window reports Used textures: 12 - 6.0 MB, which is the size of the textures without mipmaps).

I have another plane with two materials using a:
256x256 RGB DXT1 42.7 Kb
1024x512 RGB DXT1 341.4 KB

The render stats window reports:
Used Textures: 2 - 384.0 KB

This is almost the combined size of the compressed textures as shown in the preview window: 42.7+341.4 = 384.1 Kb

I would have expected a size of 3 MB
256*256*32*1.333*/8388608 = 0.333
1024*512*32*1.333*/8388608 = 2.66

So it seems to me that in this situation the render stats window is reporting the texture memory in a different way.

Also, while I have your attention
VRAM usage reports two numbers, xx MB to yyy MB, What are these two limits? I can't find an explanation anywhere.

Thanks in advance

 

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