One Miscoded Expense Line Kept Reappearing for Five Years

The situation

Dewi opened the letter from the Canada Revenue Agency on a Tuesday, expecting the usual notice of assessment that arrived every spring. Instead it was five envelopes' worth of trouble folded into one, a reassessment package covering not the year just filed but four years before it. Dewi ran an incorporated welding inspection practice out of Port Hope, doing structural and pipeline inspection work for contractors across the region, and had built the business slowly after leaving a shop floor job as a welder to work independently. The corporation was small: one office, one truck, and a bookkeeping system that had barely changed since the first year of operation.

Rajesh, Dewi's spouse, an IT support lead for a logistics company and the corporation's co-director on paper, handled the household side of the finances and had never looked closely at the annual returns; that job had always belonged to Anjali, the bookkeeper who had prepared the corporation's books and filed its returns since it was incorporated. In the first year, Anjali had set up a template for claiming vehicle and home office expenses against the corporation's income, built around a set of assumptions about business-use percentages that were, at the time, reasonable enough.

The problem was that the template never changed. Every year after, the same percentages, the same categories, and in at least one case the same dollar figure for a recurring expense were carried forward without anyone checking whether they still reflected how the business actually operated. By the third and fourth years, the vehicle was being used differently, a chunk of the home office had been converted back to personal space, and the numbers on the return no longer matched anything real. None of this was deliberate. It was the kind of drift that happens when a small business relies on last year's file as this year's starting point and nobody stops to ask whether last year was right.

The CRA's letter did not accuse Dewi of anything dramatic. It flagged a pattern across five consecutive returns, requested supporting documentation for the vehicle and home office claims, and gave a response deadline that was uncomfortably close. The amount in dispute, once the reviewer finished totalling the adjustments across all five years, sat somewhere in the range of fifty to a hundred and fifty thousand dollars in additional tax, interest, and potential penalties. For a business that size, that was not a number Dewi could absorb without a serious fight, and it was clear from the letter's tone that the CRA intended to treat every year the same way unless someone gave them a reason not to.

What the review found

Before responding to the CRA, we asked Dewi to gather five years of vehicle logs, lease and purchase records, utility bills, floor plans, and anything else that could show how the business-use percentages had actually shifted year over year. What came back told a clear story once it was laid out chronologically. The error had a single origin: a business-use percentage set in the corporation's first year, built on an early estimate of how much the vehicle and home office were used for inspection work rather than personal purposes. That estimate had never been revisited.

Anjali had simply rolled the prior year's figures forward each time a new return was prepared, treating the template as a fixed input rather than something to be checked against what had actually happened that year. In the first year, the estimate was defensible. In the second, the business had grown and vehicle use had genuinely increased, so if anything the corporation had underclaimed. In the third year, Dewi bought a second, more efficient vehicle and split its use between two purposes in a way the template never captured. By the fourth year, part of the home office had been converted to a spare bedroom after a family member moved in, which meant the claimed square footage no longer existed as claimed space at all. The fifth year, the one that triggered the CRA's original review, simply repeated the fourth year's numbers without adjustment.

Laid out this way, the review found that the error was not a pattern of aggressive claiming but a failure to update a single template, compounding in one direction for two of the five years and running in the corporation's favour, if anything, for a different stretch. This mattered because it changed what the case actually was. The CRA's opening position treated all five years as a consistent overstatement requiring the same correction and the same penalty treatment.

Our review showed that two of the years had genuine, documentable support for the claims made, one year was essentially a wash, and only two years contained real overclaims that needed to be conceded. That distinction was the difference between a reassessment across the full five-year span and one narrowed to the years where the numbers genuinely did not hold up. It also mattered for penalties: an unbroken five-year pattern reads to a reviewer as a chosen practice, while two isolated years with a documented, non-deliberate cause reads as an oversight corrected as soon as it was found, which is a materially different footing for negotiating penalty relief.

What we did

1. Requested the complete CRA audit file before responding, so we understood exactly what the reviewer had already concluded and which years carried the largest proposed adjustments, rather than guessing at the CRA's reasoning from the reassessment notices alone. This let us target our response at the specific assumptions the reviewer had made about the vehicle and home office claims, instead of re-litigating years that were not actually in serious dispute, which saved time on both sides and kept the file focused from the start.
2. Rebuilt the business-use percentages year by year using Dewi's original records, cross-checking mileage logs, fuel receipts, and the floor plan changes against what had actually been claimed on each return, so that every number we eventually presented to the CRA was tied to a specific document rather than an estimate. This produced a year-by-year table that made the origin and shape of the error visible for the first time, something neither Dewi nor the CRA's reviewer had been able to see from the returns alone.
3. Separated the five years into three categories, genuinely supportable, a wash, and overclaimed, and prepared a written submission explaining why the error was confined to specific years rather than reflecting an ongoing practice, with the documentation for each year attached so the reviewer could verify the distinction independently rather than take our characterization on faith, which mattered given how the CRA's original letter had treated all five years alike.
4. Pushed back in writing on the CRA's initial proposal to apply gross negligence penalties across all five years, arguing that a single uncorrected template error, once identified through the client's own cooperation, did not meet the threshold for that level of penalty, and asked for the file to be reviewed on the actual facts of each year rather than the total span, since a five-year label obscured how different the years actually were from one another.
5. Negotiated directly with the reviewer once the CRA's position shifted midway through the file, when a supervisor's review moved the agency toward a harder line on the two genuinely overclaimed years even as it accepted our documentation for the other three, which meant re-opening a settlement conversation we had thought was close to finished and preparing a second round of documentation to hold the line on the three years already supported.
6. Arranged a payment plan for the confirmed balance once the reassessment was narrowed to the two years, so Dewi's corporation could pay the amount owing over time rather than in one lump sum that would have strained its cash flow at a point when several client contracts were still outstanding and payment was not yet in hand, and structured the schedule so the largest installments fell after those invoices were expected to clear.
7. Set up a documentation and review process with the corporation's bookkeeping going forward, including a yearly check of the business-use percentages against actual vehicle and home office usage, so the same drift could not recur the next time a return was prepared from the prior year's file, with a simple checklist Dewi and Anjali now run through together before each filing.

The outcome

The final result was a reassessment narrowed from five years to two, with the corporation conceding the overclaimed portion of those two years' vehicle and home office expenses rather than fighting a claim the documentation could not support. The additional tax, interest, and reduced penalty came in near the lower half of the range the CRA had originally proposed across all five years, in the neighbourhood of seventy thousand dollars once everything was totalled, a meaningful sum but well short of what the corporation would have owed had the CRA's opening position across the full five-year span held.

This was not a case where the client walked away clean. Two years of claims genuinely did not hold up, and Dewi's corporation paid tax, interest, and a penalty on those years because the numbers on the returns did not match what had actually happened in the business during that period. That outcome was disclosed to Dewi plainly at every stage; the goal from the start was to limit the damage to its actual source rather than promise an outcome the facts did not support.

The mid-file shift in the CRA's position, when a supervisor pushed for a harder penalty stance on the two problem years even after accepting our documentation for the other three, added several weeks to the process and required a second round of written submissions before the file settled. It was a reminder that a reassessment file is not necessarily resolved once a reviewer signals agreement; positions can move until a settlement is actually confirmed.

Since the file closed, Dewi's bookkeeping now includes an annual check specifically built to catch the kind of drift that caused the problem in the first place, and the corporation has filed two subsequent returns without any further CRA inquiry into the vehicle or home office claims.

What you can learn from this