I don't own one of these valve bodies (yet), but this is how I understand it, please correct me if I'm wrong....

You are correct in that the auto/manual is nothing more than a regular automatic valve body. The idea of the auto/manual valve body is simply that it already has a shift kit installed. So, if you have it in D, the automatic shifts will be much crisper, or you can shift through them manually... your choice.

I assumed you WILL need a kickdown because you do not shift it manually back to first until AFTER the car comes to a full stop.