Won't work, CobraEye, apparently this setting doesn't apply to water. You can set it to 1 or 12, it will be just the same. This parameter only works when the reflectivity channel is active, not this "fresnel like" reflectivity that is activated in the transparency channel. As for transparency, it is always computed the same, I don't know why this parameter is active for transparency.
And it's Infinite only, btw.