Oddity in Setting Background Colors in Finder

If I change the background color in a Finder window using View Options the color selected using the Colors pane and using the RGB sliders option the resulting color as shown by Digital Color Meter is not the same as that which I set. For example, If I select the RGB values 180-190=180 Digital Color Meter reports that as 193-193-193. This oddity, at least as far as I've investigated, only occurs when setting the background colors for Finder. With other applications, and using the same Colors pane, the results, when checked with Digital Color Meter, are exactly those I selected. I'm running OS X 10.6.1 on a MacBook Pro.