NLA and timeline manipulating

I make an NLA sequence. After that I want to change the timeline.
I go to the IPO editor and click time and add a driver, in the
box there is an object field present. After that I can insert
a keyframe and I see a timeline. The problem is that when I use
this timeline to make different times, the curvepath is getting
shorter in time, e.g. The animation is getting shorter than before.
By the way, I also have that I can only insert a new curve, or add
a marker with M.
To me this is completely new in opposite to the NLA tutorial
of the blender documentation.

Is this the purpose of the timeline or is there a better way to do

Did anybody noticed a diffrence sinds the tutorial in blender 2.37?