The ideal is if you follow the guide, it will work.
Not the case with your DDSopt guides.
I haven't gone through each one, I was using the skyrim one, but I suspect they all lack one vital piece of information that guarantees success. That piece of information is that ddsopt refuses to work on any textures which are not in a folder called "textures". If for example, the textures are in the root of a folder called "process" and this is selected as the input folder, then the textures will at best be copied over to the destination folder if under the ignore header the "copy unprocessed and ignored files" flag is checked. You might think well that's obvious; incorrect. Do you know how many people have stated and correctly stated that ddsopt doesn't work all because of this simple omission from your guides. This is stupid.
Do the right thing, update the various ddsopt guides to include this omission. What hardcoded non-sense.