Bunching two kids' dental and vision costs into one window

The situation

Nadia noticed the problem while sitting at her kitchen table with two shoeboxes of receipts, trying to figure out why the number on her notice of assessment did not match the number she had entered on her return. She had moved back to Ottawa the previous year after nearly a decade working abroad, bringing her two sons with her, and the first year home had been expensive in ways she had not fully planned for.

Both boys needed dental work that had been delayed while the family was overseas, one starting orthodontic treatment and the other needing a full vision correction after a school screening flagged a problem nobody had caught. Nadia, working as a personal support worker while she rebuilt her Canadian credentials, had timed the appointments as best she could to fit her income and her sons' school schedules, not with any tax planning in mind. When her brother Rejean, who had stayed in Ottawa the whole time, helped her do her taxes that spring, he pointed out that the medical expense credit lets a claimant choose any twelve-month period ending in the tax year, and that bunching the orthodontic and vision costs into one such window, rather than splitting them across two calendar years, could meaningfully increase the credit.

That is what she did. The claim included braces payments, vision assessments, and corrective lenses for both boys, all falling within a twelve-month window she and Rejean had selected to capture as much of the spending as the rule allowed.

Weeks later, a letter arrived asking her to substantiate the claim and questioning whether all of the expenses genuinely fell within the window she had used. Nadia's first reaction was not anger but fear. She had just stabilized her finances after the move, was still learning how the Canadian system worked after years away, and the letter made her worry the credit would be clawed back entirely, along with whatever penalty came attached to it.

Nadia had spent the years overseas working in eldercare, an experience that made her careful about medical paperwork generally, which was part of why the letter unsettled her so much. She was used to being the one who kept records straight for other people. Seeing her own family's file questioned, in a country whose tax rules she was still relearning, felt like a different kind of problem than anything she had handled before.

What made this urgent

What made the letter urgent was not the size of the number, which sat under fifteen thousand dollars and was manageable in the context of a family budget, but the uncertainty around it. Nadia did not know whether the review would take weeks or months, whether it would expand to look at other parts of her return, or whether an error in judgment about the twelve-month window would be treated as an honest mistake or something more serious.

The rule itself is more flexible than most people assume. A claimant can choose any twelve-month period as long as it ends within the tax year being claimed, which is exactly what lets a family time appointments, when medically appropriate, to capture more expenses in one credit calculation rather than splitting them thinly across two years. The rule does not require the expenses to fall in a calendar year, and using it deliberately is not, on its own, improper.

The review had been triggered because the dates on some of the receipts, particularly for the vision portion, were close to the edge of the window Nadia had chosen, and a few supporting documents she had gathered quickly before filing did not clearly show which twelve-month period the underlying appointments fell into. That ambiguity, more than any suggestion of wrongdoing, was what had flagged the file.

For Nadia, the urgency was practical rather than legal. She needed to know, quickly and in plain terms, whether she needed to set money aside for a clawback, whether responding herself risked making things worse, and how long the uncertainty would hang over a household budget she had only just gotten under control after the move. Predictability mattered to her as much as the ultimate number, and she said so plainly in the first meeting: she did not want a drawn-out fight, she wanted to know where she stood.

Her son Marc-Andre, old enough to understand what was happening, had started asking whether the orthodontic treatment might have to stop partway through if the money got clawed back, which added a second layer of urgency that was not about tax law at all.

There was also a personal dimension to the urgency that had nothing to do with the tax rules themselves. Nadia had chosen to time both boys' treatments the way she had partly because delaying either one further, after years already lost to the move, was not something she was willing to do again. Whatever the review concluded about the paperwork, she did not want the answer to be that the family should have waited even longer to get her sons the care they needed.

What we did

1. Reviewed the twelve-month window against every receipt. We laid out each expense against the exact window Nadia and Rejean had selected, confirming which items clearly fell inside it, which sat close to the edge, and which lacked a clear appointment date that tied them to the window at all, giving us an honest picture of the claim's strength before responding, rather than assuming every dollar in the original claim was equally defensible.
2. Requested clarified documentation from the providers. For the ambiguous vision expenses, we contacted the clinic directly to obtain itemized statements showing exact appointment and payment dates, since the original receipts Nadia had gathered quickly before filing did not clearly establish timing on their own, and a clinic's own billing system is usually a more reliable source for exact dates than a handwritten or abbreviated receipt.
3. Confirmed the window selection was permitted, not just convenient. We prepared a clear explanation of the twelve-month window rule and how it applied to Nadia's chosen period, making the point directly that selecting a window to capture more eligible expenses in one year is an allowed choice under the credit's own design, not an aggressive position, and we wanted that framing on the record early so the review did not proceed on the mistaken premise that the window itself was the problem.
4. Separated the strong claims from the weak ones. Rather than defending every dollar as equally solid, we identified the portion of the claim, tied to the ambiguous vision receipts, that genuinely could not be fully substantiated even with the clarified documentation, and treated that portion differently from the rest, since defending a weak claim as vigorously as a strong one tends to weaken the credibility of both.
5. Responded with the full window, evidence, and a proposed adjustment. We submitted a response defending the bulk of the claim in full, supported by the clarified provider statements, while proactively proposing a modest reduction on the weaker vision portion rather than waiting for the reviewer to challenge it and risk a worse outcome, which also signalled that the rest of the claim had been prepared carefully rather than opportunistically.
6. Kept Nadia informed at each step with a plain timeline. Because predictability mattered to her more than squeezing out every dollar, we gave her a realistic estimate of how long the review would likely take and updated her promptly whenever the file moved, so she was not left guessing for weeks at a time, which mattered as much to her as the eventual dollar figure did.

The outcome

The review concluded with most of the claim upheld as filed. The orthodontic expenses and the bulk of the vision costs were accepted within the twelve-month window Nadia had chosen, once the clarified provider statements confirmed the dates. The portion tied to the ambiguous vision receipts was reduced, reflecting the genuine gap in documentation rather than any finding that the window itself had been used improperly.

The net adjustment came in well below the original amount flagged, and Nadia paid a modest difference rather than facing the full clawback she had initially feared. No penalty was applied, since the review concluded the discrepancy was a documentation gap rather than an improper claim.

For Nadia, the more important outcome was the one that is harder to put a number on. She had a clear, early sense of roughly where the file would land well before it closed, which let her keep the household budget steady through the process instead of holding money in reserve against an unknown worst case. Marc-Andre's orthodontic treatment continued without interruption. Rejean, who had suggested the window strategy in the first place, kept better records for the family's future claims, using the clarified documentation approach as the template going forward.

Nadia has since started keeping a simple log of appointment dates and payment amounts as they happen, rather than reconstructing them from receipts months later at filing time. It is a small habit, but one that grew directly out of watching how much of the review's length came down to ambiguous paperwork rather than any real dispute about whether the expenses themselves were legitimate.

What you can learn from this