One reason it may appear the result is different is that you may be working on a high res image.
When at 100% view your screen is most accurately displaying your image at 1 pixle of data to 1 pixel of screen. Lets say say you are at 10% view, then your screen is trying to display the image correct, but the interpolation may make then look darker, lighter, bolder as 10 pixles of data are crammed into 1 pixel of monitor. That is why Adobe so wisely chose the default view for effects to be 100%.
If your image is low res, your problem may be somehting I have not yet seen. If so let us know if this happens to all images with sumi-e ro just that type of image. Obviously screen shots in this case make it easier to answer your post if at all possible.