I think OUR shades are held on by brackets UP, way UP on the inside top of the valance. To take them off becomes an exercise for yoga fans! And, I think you need that square headed screw driver thingy (oops there is that word again!).
Ya gotta get the valance off first, there is no doubt about that. Then work on getting off the shades.
Isn't "thingy" in the dictionary yet?? You are forgiven!
Your description of raising shades is very good, may I add, that we also kinda roll that grabber thingy (oops), aka, the handle. If you roll it out a bit and also put just a tad pressure to pull it away from the window and then raise or lower slowly with even pressure, that helps. SteveR has a great way to describe this, I believe we learned that rolly trick thingy from him. (more thingys than I know what to do with here,
Knock on wood, we have only had one bad shade and that was over the desk and the holes that the cord goes through enlarged.
We have a love/hate issue with our shades, specially since we have no drapes!