Hi progress. Thanks for sticking with me.

Steps to reproduce:

1. Launch Photoshop
2. Edit -> Color Settings
3. Choose "North America General Purpose 2" (i.e. sRGB etc.)
4. File -> New
5. 32 x 32 pixels, white background
6. Channels tab, create new channel. All black "Alpha 1" channel appears.
7. Set foreground colour to 62, 62, 62.
8. Edit -> Fill with foreground colour, Normal blending.
9. Eyedropper, point sample, anywhere in the alpha channel.
10. Check foreground colour: it's 61, 61, 61. First evidence!
11. File -> Save As, TGA, with alpha channels. I called it "test.tga" on my Desktop. 32 bits per pixel, no RLE.
12. Examine the TGA file. I use "hexdump"

rb@Crane$ hexdump Desktop/test.tga
0000000 00 00 02 00 00 00 00 00 00 00 00 00 20 00 20 00
0000010 20 08 ff ff ff 2c ff ff ff 2c ff ff ff 2c ff ff
0000020 ff 2c ff ff ff 2c ff ff ff 2c ff ff ff 2c ff ff
* 0001010 ff 2c 00 00 00 00 00 00 00 00 54 52 55 45 56 49
0001020 53 49 4f 4e 2d 58 46 49 4c 45 2e 00
000102c

Note that the alpha channel contains the value 0x2c, which is 44, and not 61 or 62.

Please let me know if you see something different.