To properly explain how xtool behaves. The plugins I post here should be considered "external" plugins, there are also plugins in xtool called "internal" plugins. These are just common compressors used in games, zlib, lz4, lzo and etc. Since some internal plugins have issues detecting streams by themselves, lz4 as an example. What normally happens is, the external plugins I post here give information to the internal plugins. Telling them exactly how the streams are found and where to look for them. So if you use a plugin like frostbite3 and don't add zlibwapi.dll, liblz4.dll and etc. Basically no libraries whatsoever. When the external plugins give information to the internal ones. They will refuse to accept streams or any of the information as they didn't initialize because of missing libraries therefore no error is given however the ratio is affected. You can try it now yourself, use any of the plugins without the required libraries, xtool will just give a result of 100% ratio and no error. Encoding is never a problem, the problem starts when you are decoding, if you used something when encoding but it's missing when decoding. XTool will give you an error telling you a certain method was not found.
Edit:
This is what I told this person
here, to run xtool without stdio so that I can see the error message that xtool gives.
Here's an example, I used zlib method when encoding and then I removed zlibwapi.dll and then tried to decode.