You should create a "Reset to Default" button or preset that resets Voukoder back to it's default configuration settings. Currently, it's impossible, as far as I know, to do this unless you delete all your presets (which is rather annoying).
I don't think any screenshots are needed for this request, let me know if any other details are needed.
You can switch to another exporter and back to voukoder as a work around.
This will be available in Voukoder 2.0
Actually, even using this method it does not work. Since I have several presets, it simply defaults back to my last preset configuration.