One factor that can impact programming is how DMX values are displayed. A single channel of DMX has 256 different values, with the possibility of a unique feature corresponding to each DMX value. (A great example of this is the Visual FX channel in Catalyst.) If a console displays that particular channel in percentages instead of straight DMX values, you as a programmer will likely have a hard time dialing in the exact value you need without skipping a few settings in between each turn of the wheel.
-From Vickie Claiborne's upcoming Video Digerati column
