A lot of questions there but if you want the "states" to change instantaneously from one to the other you need to go to the keyframe editor for the widget and change the interpolation to Constant. Linear interpolation will give you a linear change from one value to another.
Also note that the widget slider is a parameter control just like any other and the same rules apply - it sounds as though you are expecting a different kind of behavior.
Simon Ubsdell
http://www.tokyo-uk.com