If you are using the colour picker tool (the pipette) in the Material Editor to copy or duplicate colours, then you should be aware that the colour picker samples the program interface NOT the colour field that you might be trying to copy.The colour fields only have a very small area in which the exact colour can be sampled (in the image this area is marked in white) The light blue area samples the colour one less than exact colour. Try it now, and click on a white colour field. It will sample as 254,254,254 and not 255,255,255.
If colour accuracy is important to you use the colour picker on the right edge of the colour field to get the exact colour.
(Discovered on a printout from an old Usenet Bryce Group for Bryce 3 and 4! Even in Bryce 6.1.3 this “bug” still is around)