As the war of words over the handling of a multibillion dollar fighter jet procurement process continues, the man responsible for advising the government on what the military needs says he's standing behind his choice.

In a scrum with reporters in Ottawa Monday, Canada's top soldier Gen. Walt Natynczyk said, "I can put my hand over my heart and say I've provided the government and Canadians with the very best military advice."

When asked whether that includes the recommendation Canada purchase a fleet of F-35 stealth fighter jets, the Chief of Defence Staff answered simply.

"In my mind, yes," Natynczyk said, explaining he reached that conclusion on the advice of experts under his command.

He also had to meet various requirements laid out by the Government -- that Canada's armed forces be capable of working with our potential allies, that we continue to be a "strong, reliable partner" with the United States, and that this country's military project leadership abroad.

"And so in my mind, the F-35 as it's developing -- and again this is a research and development project that has come a long way -- I mean, it's flying."

Last week, Auditor General Michael Ferguson tabled a report that outlined a litany of criticisms aimed at the government's handling of the jet procurement process.

Besides failing to publicly disclose complete cost projections, even after Parliamentary Budget Officer Kevin Page reported the F-35s would wind up costing Canadians far more than they had been told, Ferguson said there was an overall lack of oversight on the process.

On Sunday, Defence Minister Peter MacKay said the difference between the projected $15 billion cost Canadians had been told and the $25 billion Ferguson said it would actually wind up costing boils down to a matter of accounting.

"The additional $10 billion was money that you could describe as sunk costs," MacKay told CTV's Question Period, suggesting that those monies would be spent no matter what jet Canadian Forces are flying.

"So there's a different interpretation," he said, acknowledging he knew of the discrepancy as far back as 2010.

"But the way acquisitions have always been done is to key in on the actual costs of new equipment and that is the way that this number was arrived at."

Reporting from Ottawa where she's been digging through past procurement files, Â鶹´«Ã½ Channel's Mercedes Stephenson said MacKay's claim may not fly.

"In some procurements it clearly states this does not include ‘sustainment'," Stephenson told Â鶹´«Ã½ Channel, referring to the maintenance costs inevitably associated with any equipment purchase. The F-35 procurement documents make no such reference, she said, noting there appears to be no record of anyone from government pointing to the accounting issue either.

In his interview Sunday, MacKay sought to assure viewers that however the process may have been mishandled in the past, the government was working to fix them going forward. The auditor general's recommendations are being implemented, MacKay said, including shifting the procurement out of his department to Public Works.

"Obviously, there is a need to improve the way that we are reporting both to Parliament and to the public," MacKay said, nevertheless insisting there was no need for him to resign over it.

In a message posted to the social media website Twitter Monday, Interim Liberal Leader Bob Rae made it clear he sees things differently.

"Peter Mackay says F-35 is an ‘accounting' issue. Close, but not quite - it's an ‘accountability' issue - just read the AG report," Rae wrote.

The government line however, reiterated by MacKay in his CTV interview Sunday, is that Canada hasn't spent or lost money on these jets yet.

But in his appearance on Question Period, Liberal Deputy Leader Ralph Goodale said a trail points straight to the Prime Minister's Office, where Harper would have been kept apprised of the file from the beginning, including Treasury Board briefings dating back to 2006.

"He knew all the details and he misled Canadians," Goodale said.