Asking your agent for feedback after an audition sounds like a good idea.
But does the feedback assist you, or does it make you self-conscious? Everyone may be doing it but does it help you. If it helps you, then great.
Before you ask for feedback some questions are worth asking, such as: what is the process for getting the feedback to you, and under what conditions is the feedback being considered?
Just imagine if your agent asked a casting director for feedback only two days after your audition. The casting director may have seen fifty people that day in five categories and maybe the same again the next day. What can they remember and what can they say?
Don’t forget the pressure agents and casting directors are under. They’re busy doing their work.
Any comment that comes back to you from a casting director via the agent has enormous weight. It’s often critical and can, at times, be quite damaging to your confidence. A comment is sent to you and there is no discussion as to its meaning, and if it’s dire then there you are left holding it. ‘He’s too theatrical!’. It can stay on your mind for a long time.
Why not let the casting directors and agents do their work and you do yours.
Work on your craft with your acting coach in rooms where the critical discussion is full and does support your practice.
Asking for feedback might sound like a good idea - the reality might be something different.