mcdhu
you are right. I usually "pre-retard" the donuts towards the thrust and then retard fully when I think is necessary.
The retard call out is not a command. It is a reminder for you not to forget retarding the levers. Forgetting it has killed quite a few people already and know there is a relatively new red ECAM warning if you do forget, I believe.
The partial spoiler helps a lot in this airplane, by the way.