Glenn,
Yes - the awning can be stopped anywhere inbetween and it works the same (tensioner tight at all positions). I have run it partially out at rest stops where the guy parked next too us was too close to fully extend the awning. Made him a little nervous when I started running it out
.
Also - Keystone uses the Carefree Travlr. The Travlr power arms work on your existing A&E roller and fabric. For those wanting to convert, you can save a little money by just getting the A&E power arms and retaining your existing fabric, tube, and awning rail. Works just the same. That's how we did it, as our awning was brand new and seemed a waste not use some of it.