I can't see how you could agree. decisions being subject to prior inputs and processing are shaped and formed by that process, as is conscious will.
Decisions can be influenced by prior inputs but they can also be influenced by ideas in the mind about future consequences, even bad ideas, even delusions.
The mind can use many things, even emotions if one is inclined, to make decisions, but it is the mind, an aspect of brain activity, not the brain itself, making decisions.
They can also be capricious and rapid and unpredictable, like all the decisions made when dancing. A skill that only improves with practice.
How one uses their mind is entirely dependent on how they have practiced using it.
Some can have a sloppy will and some a precise. It is up to the individual to decide.
Not their brain. And they can decide at any waking moment to make their will more precise by practicing it.