Dozens of veterans across Canada were shortchanged $600 a month for seven months due to what Veterans Affairs calls a rounding error.

In November, 133 veterans were retroactively paid the cash they didn't initially receive.

The error came about in April 2017, when the federal government made changes to what is now known as the Career Impact Allowance, a benefit provided when a vet's employment options have been limited because of a service-related illness.

2 tours in Afghanistan

"I got a letter saying, 'No, you don't meet the criteria for a higher grade,'" says Dennis LeBlanc, of Hanwell, N.B., southwest of Fredericton. He lives with post-traumatic stress disorder after doing two tours in Afghanistan and was medically released from the Canadian Armed Forces two years ago.

Dennis LeBlanc in Kabul, Afghanistan in March 2012. The 11 month tour was the first of two for him in the country. (Submitted by Dennis LeBlanc)

LeBlanc, 41, noticed that something wasn't right about the way Veterans Affairs had calculated his disability benefits. He reported the matter to the Office of the Veterans Ombudsman which informed Veterans Affairs. When the department investigated, it determined it had incorrectly rounded LeBlanc's time served.

Entitled to more money

The Career Impact Allowance is based partially on the number of years a veteran has left to serve, with people who have served longer entitled to a lower benefit.

"The Career Impact Allowance is actually designed to reimburse people for their loss of ability to generate retirement income, so the earlier you get injured in your career, the more of a loss there is," explains Veterans Ombudsman Guy Parent.

LeBlanc had been placed in the group for people who have only five years left to serve, with the lowest allowance. He actually had 5.52 years left to serve, which means he was entitled to more money.

LeBlanc and the other veterans affected are now receiving $1,199.93 per month, instead of the $599.96 per month they were receiving.

"That's a car payment, that's my kids education fund," says LeBlanc. "I mean, it was huge."

Canada's Veterans Affairs Minister says his office corrected the error as soon as it became aware.

'How the system is meant to work'

"This is how the system is meant to work. The ombudsman brings this to our attention, we listen to veterans and we check the system," says Seamus O'Regan.

Former Member of Parliament and longtime veterans advocate Peter Stoffer credits Veterans Affairs for correcting its mistake, but he has a message for veterans.

"I encourage all veterans, military and RCMP to go back into their own files, their own claims and make sure that they indeed are receiving all the benefits they're entitled to," Stoffer says.

The ombudsman says he's confident the calculations are now correct and people are being treated fairly.

Dennis LeBlanc says it's gratifying that catching the mistake in his own files helped so many others.

"Part of my regimental motto was 'never pass a fault' and that's clearly a fault," he says. "I let the system do its thing and it actually worked."