An Garda Síochána inaccurately recorded 6.4 million breath tests at one stage, it has been revealed.
As watchdogs and politicians continue to seek answers for the scandal of bogus drink and drug-driving checks, senior officers said the scale of the crisis was initially more than four times the final figure of 1.4 million.
The Oireachtas Justice Committee was told the 6.4 million figure for breath tests was a recording issue that was corrected overnight, not deliberate falsification.
"That just goes to show the impact of difficulties about how all this data was recorded," Assistant Commissioner Michael O'Sullivan said.
Following his inquiry, which found that more than 40,000 breathalyser checks were supposedly carried out on drivers every month from 2009 to 2016, regional Garda chiefs have been asked to launch further investigations into 2,134 drink and drug-driving checkpoints and associated data which contributed to the massive over-exaggeration.
Garda assistant commissioners in charge of relevant regions have been asked to run the investigations and their work is being overseen by Assistant Commissioner Michael Finn, who has authority for roads policing.
The committee was told no disciplinary inquiries or proceedings had been taken against any officer so far.
Acting Garda Commissioner Donall O Cualain said: "Where people have been found to have done something wrong, they will be held to account, regardless of their rank."
The top officer repeated assertions that there is no evidence that senior Garda management knew about the widespread falsification of breath test data.
"There's nothing to suggest otherwise," he said.
Mr O Cualain said the Policing Authority's report on the scandal, due to be submitted by financial auditors Crowe Horwath in the coming weeks, would help advise what action would have to be taken internally.
"I'm not ruling anything out at this stage ... we have to get the full picture," he told the committee.
"At that stage we will establish who is accountable and how they might be held to account."
Mr O'Sullivan, whose report found bogus breath tests were put on the Garda's Pulse database because of recording issues, potential inflation of numbers and estimations, rejected claims that false data was being created by officers to enhance their career prospects.
"They [the claims] weren't dismissed. They weren't substantiated by any other evidence or supporting corroboration," he told the committee.
The startling revelations about the gross exaggeration of drink and drug-driving checks from 2009 to 2016 included 3,498,400 breath test records on Pulse when only 2,040,179 were actually carried out.
The committee was told it would take 21 years to listen back to the 502,000 calls reporting bogus numbers to the Garda Information Services Centre in Castlebar.
Mr O'Sullivan also rejected the way the breath test scandal was categorised by some committee members, adding: "What I have referred to in the report - it was not a deliberate inflation ... we have put it as estimation."
Committee chairman Caoimhghin O Caolain said: "I don't think anyone of us would buy the notion that this was all about estimation.
"Falsification is the word that we have used.
"At the end of the day the public's belief is falsification."
The politicians are also looking into failings in traffic policing that led to the wrongful conviction of 14,700 motorists for driving offences because of issues with the fixed-charge notice system for fines and penalty points.
Some motorists found driving without an NCT certificate had not received a notice in the post and were prosecuted without having an opportunity to pay a fine.
Others were taken to court even though they had received a penalty and paid a fine for issues like having not tax, driving unaccompanied while a learner or not displaying L plates.
Almost 12,000 motorists with wrongful convictions have been contacted and 3,800 are set to have the conviction wiped off their licence in the courts in December.
The bill for the wrongful convictions is currently estimated at about one million euro.
Mr Finn revealed that 119 lawyers had already made contact with Garda Headquarters on behalf of clients to raise concerns over the impact a criminal record has had.
More legal letters are arriving every day, he told the committee.
It is understood these contacts from solicitors are not connected to the appeals process or seeking convictions to be overturned in the courts.
Elsewhere, Mr Finn disputed media reports that motorists wrongly convicted for motoring offences had been imprisoned as a direct result.
He said: "I can categorically say that nobody went to jail specifically for one Fixed Charge Notice."
"It's possible that persons who opted to not pay the fine did end up inside in prison.
"We are working with the Courts Service and solicitors to identify those cases. There may well be civil actions in relation to that."