And Wallin's assertion that Senate bookkeepers failed to detect mistakes in her travel claims that she later spotted appears to be at odds with the upper chamber's version of events.
Conservative Sen. Carolyn Stewart Olsen and Liberal Sen. George Furey tell The Canadian Press that Senate finance officials formally brought irregularities to the attention of their committee in early November last year.
The three-senator steering group of the internal economy committee then forwarded the travel-claim matter to independent auditors on Nov. 29.
Wallin told CBC television's chief correspondent Peter Mansbridge on Thursday that she identified problems before the audit.
"The problems that we discovered — and long before there was any audit, my office got on this — I've got a staff of two and me and we spent every night, and we are still there, going through," Wallin said.
"So we started to see problems, where things that should have been charged to a third party weren't."
Wallin also said she kept Prime Minister Stephen Harper's chief of staff Nigel Wright "in the loop" as her office sorted through the expenses. She had also told Wright she had paid back some of the money.
If Wallin had indeed detected problems before auditors acquired her file in November and began paying back expenses, neither she nor any other Tory said so in February when the issue blew open in the media.
Harper told the Commons on Feb. 13 he had reviewed her numbers and had no concerns. Wallin also revealed nothing about her unilateral probe of her books when she wrote an op-ed in the Globe and Mail.
"The (Senate travel) system is based on annual travel points per senator, so we are all treated equally — we have the same number of flights, regardless of distance," Wallin wrote.
"And I have never exceeded my designated points. If I did, I’d be on the hook for any costs."
Conservative Sen. David Tkachuk, the former chairman of the internal economy and steering group that sent the matter to auditors, also defended her high travel claims.
"She's a celebrity. She gets tons of invitations to speak," Tkachuk told the Saskatoon Star-Phoenix. "I wouldn't put up with her schedule."
Wallin also told the CBC Thursday that $38,000, or potentially more, in problematic claims appeared to slip through the finance group — the same accounting group that approached the committee.
A source familiar with the process told The Canadian Press that Senate administrators had begun dealing formally with the irregularities last August.
Wallin had been caught up in a random audit triggered by the auditor general's report last year.
"I mean, you have a failsafe in there, which supposedly is the Senate finance system, that's supposed to check that," she said in the interview.
"You know, I didn't have travel claims rejected. But there were mistakes."
In response to questions Friday about when the mistakes were discovered, and by whom, Wallin's office would only say she stands by the interview.
"Everybody's contrite when they're before the judge, but if she's truly a servant of the public, she needs to provide us with a more substantive explanation of what happened," NDP ethics critic Charlie Angus said Friday.
The independent review of Wallin's expenses by the firm Deloitte is expected to be presented to the internal economy committee in late July.
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