noise removing in 2.5: the previewing window gives a false rendition

while adjusting noise reduction (with denoise option checked on) in topaz adjust2.5, there is a big difference in what you see in the preview window compared to what you get after clicking OK. It does this when you are not seeing the picture at 100% in the zoom option(by default or when you click on fit).

it does this with any presets i have tried. You must have the denoise option ON and not at 100% zoom level to see the problem Here is the image i used to make my tests. If you try it, you will clearly see what i mean while looking at the background. The results are so pleasing in the preview window and not so great after clicking ok. The resulting image is still full of artefacts while it was showing smooth surfaces in the preview mode. The preview is the result i want :o)

thank you !