An attorney who oversaw Donald Trump’s income tax returns in the mid-1990s said the Republican presidential candidate had little interest in the tax code — contrasting with the billionaire's claim that he understood taxes "better than anyone" who had run for the White House.

“As far as I know, and that only goes through late '96, he didn't understand the code,” said Jack Mitnick, a former tax adviser for Trump, in an interview with NBC's TODAY. "Nor would he have had the time and the patience to learn the provisions. That's a lifetime of experience.”

Mitnick oversaw Trump’s income tax returns in 1995, portions of which were published Saturday by the New York Times. The documents showed a reported loss of nearly $916 million — a deduction tax experts hired by the newspaper said was so large that Trump might have legally avoided paying federal income taxes for up to 18 years.

Trump responded to the report on Twitter: "I know our complex tax laws better than anyone who has ever run for president and am the only one who can fix them” — a stance he has repeated on the campaign trail.

I know our complex tax laws better than anyone who has ever run for president and am the only one who can fix them. #failing@nytimes — Donald J. Trump (@realDonaldTrump) October 2, 2016

Mitnick, however, told the TODAY show Tuesday that Trump was “not at all” involved in the 1995 filing.

“He was interested in the bottom line, not the detail,” Mitnick said. "Staff under my supervision did his returns - he had no involvement in the preparation."

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Mitnick, a CPA and attorney who did taxes for Trump from the 1960s to 1996, said that when Trump was married to Ivana, she was the one more likely to ask questions about how the taxes were prepared. Mitnick said that Trump's father Fred was very detail-oriented, while the younger Trump was more of a "concept" man.

"He knew that we would produce the lowest possible tax for him within the law. And he never went into the details," said Mitnick, who said it took him six months to prepare Trump's taxes. "He understood that he had to rely on us to generate the returns, that it was beyond his knowledge."

There is nothing in the Times report to say whether Trump used tax rules to avoid paying any federal income taxes following the 1995 filing.

Jack Mitnick during an interview with the Inside Edition on Oct. 4, 2016. You Tube

Mitnick said all of the documents published by the Times appeared authentic, but did not confirm whether Trump used his business losses to offset personal income taxes in 1995 or the years that followed.

“That's a conclusion you have to draw for yourself. I won't comment on that,” he said.

He added: "You're making a false assumption. You're assuming that the loss was generated in '95. Without the detailed schedules from a return, I can't even tell you of my own knowledge, when the loss arose."

He also criticized the Times for "extrapolating" that Trump could have avoided taxes for nearly two decades. "it was impossible for anyone looking at one page out of the '95 tax return to extrapolate forward and say that for 20 years he wouldn't have paid any tax."

Mitnick said that he and his accounting staff acted “in accordance with the law and regulations” to yield the lowest possible taxes for Trump.

“I thought it was wrong from a philosophical standpoint,” said Mitnick. “But it was the law. It’s what Congress enacted. We would be derelict in doing our duty if we didn't use it."

He added: "There are all kinds of provisions in the tax code that favor one group or another. And, by definition, they're unfair to all the others."

The Trump campaign said in a statement late Saturday that Trump “has a fiduciary responsibility to his business, his family and his employees to pay no more tax than legally required.”

The campaign added: “Mr. Trump has paid hundreds of millions of dollars in property taxes, sales and excise taxes, real estate taxes, city taxes, state taxes, employee taxes and federal taxes.”

Trump supporters Rudy Giuliani and Chris Christie on Sunday said the Times report, and subsequent speculation that the businessman may have used the tax code to not pay federal income taxes for up to 18 years, shows Trump is a “genius” and the best person to implement tax reform.

Yet Democratic rival Hillary Clinton and her supporters have used the report and the fact that Trump has so far refused to release his tax returns as a line of attack, questioning whether the businessman has something to hide.

Clinton’s running mate, Tim Kaine, pointed to the issue of tax returns on several occasions to attack Trump in Tuesday’s vice presidential debate.

Trump’s running mate, Indiana Gov. Mike Pence, said at the debate that Trump was experiencing a difficult time in his business and “used the tax the way it's supposed to be used.”