What is the purpose of a subpeona? and is this legal?

The purpose of a subpoena is to instruct someone to show up in court on a certain day, at a certain time, for a distinct reason. And a professional person can charge their going hourly rate for them to appear in court, to be paid by the person who is instructing them to be in court. If your counselor is being asked to be in court by your side, then you would be made to pay her wages while she is in court. But $112 per hour for her to be in court. Who does she work for, the President? I don't think you could be made to pay more than her hourly rate at her current job.

A subpoena is issued by the court to someone who must testify before a grand jury or court of law. If the person does not appear they will be arrested and jailed.

I am unclear about the counselor part of your question. If the counselor is your lawyer representing you how can she testify? If she testifies she cannot charge you for something she must do by law. Your question is vague.

A subpoena is a command by the court to appear at the time and place stated.

Who is issuing the subpoena. If you want her to appear, she would be your expert witness and you would have to pay her fees and shouldn't have to have a subpoena issued. If some other party subpoenas her, particularly if you are opposed, she will be entitled to regular witness fees and what you tell her will be confidential.

A subpoena is a court order to appear and testify in a matter.

I would guess it is standard practice; their time is valuable.

Yes

but not enough detail. On your behalf? At your request?

If she is subpoenaed by an opposing party, you don't have to pay

subpoena for what?

charge who?

usually get paid for their time by whoever wants them there.

get info and yes