Hi, I think the idea of Neat Image as a smart filter is a great idea, but any time I go back to tweak the parameters, it jumps to my last used parameters from the plugin, not the settings used originally in the smart filter. This will also happen if you change the order of smart filters.
To illustrate, make a Neat Image smart filter, set the filter strong so you can really see the effect. Make a Smart Filter of Other > Custom, just make it a single 1 in the middle. This will give you a filter that doesn't really do anything. Now open up another document, use Neat image, and adjust the settings to be really weak. Come back to the document and drag the Custom filter reversing the order it holds with Neat Image. At this point the image data will jump as if you changed the settings for that Smart Filter layer.