In his closing submissions, Standards Committee lawyer Paul Collins told the tribunal that he had argued a one-sided case but said the evidence was there for the tribunal to find Mr Hart guilty of misconduct.
"The tribunal is entitled to take from all it has seen from Mr Hart's conduct in this proceeding itself to draw from that a constant theme ... which is one of contempt to his professional responsibilities."
He said Mr Hart $35,000 was "grossly excessive".
The tribunal earlier heard from a lawyer who worked for Mr Hart.
She described him as a "fighter" who achieved results.
The lawyer - who along with all other witnesses has name suppression - said one family was "desperate to have the best lawyer in Auckland to represent their son" even though Mr Hart's fees were $1000 an hour.
"When the legal fees were discussed, they said: 'We'll do what it takes'," she said.
Tribunal member Brent Stanaway said he thought the family were vulnerable.
Mr Collins said: "To an unethical lawyer, vulnerability is a licence to charge large fees".
The tribunal also heard from a Queens Counsel with more than 35 years' experience as a barrister.
He told the tribunal the work could be done by a competent lawyer for $15,000 - $20,000 cheaper than what Mr Hart charged the family.
He said it was essential for lawyers to brief their clients about the likely costs of their work and what they hoped to achieve for them.
There has been competing evidence about whether Mr Hart told the family about his fees.
"This bill is more than most people earn in a year," the barrister told the tribunal.
He said the work done for Mr Hart's clients was "of good quality" but was not overly complex.
He referred to Mr Hart's submissions for name suppression as "simply a template".
"I can dictate those submissions in about five minutes."
Asked about Mr Hart's charge-out rate, he said Mr Hart was "a very experienced lawyer" but his fees were above what some partners and Queens Counsel charged.
"The fact that you have reached a certain age doesn't entitle you to charge accordingly, regrettably," said the barrister.
The tribunal reserved its decision.