Yeah, we do have reasons to worry the exact number of seats provided by Oxford. However, I wouldn't think Oxford's estimates in total seat numbers deviate more than 10% from the actual one -- partially credible evidence is that: you can check Oxford's estimate about seats in Ontario is very close to the number provided by OUAC (OUAC: 1500 ish for last few years; Oxford: 1430 assuming Lakehead 79).
So unless actual seat numbers from non-Ontario law schools are far cry from Oxford's estimate (welcome any correction with evidence), I believe the actual acceptance odds this year are likely to exceed 40% by incorporating the above two updates into accounts: 1. missing seat number of UofA. 2. Oxford's estimate of lower number seats provided by Ontario law schools.
"Acceptance odds" defines as below: the chance you can be accepted by at least one law school.

Yes, obviously I understand that the missing row changes the acceptance rate rather than the number of applications.
The number of applications piece of the equation seems credible, but the Oxford spreadsheet is too sloppy to trust the other side of the equation (i.e. the number of seats).

No matter what the number of seats provided by UofA are missing from the calculation above, it will change the acceptance odds to be greater than my original estimate (somewhere around 40%).
With respect to definition of "application", check the last page of the statistical chart and you can tell the applicants are defined under the context of "academic year", which refers to applicants for law school application instead of for writing LSAT (we all know LSAT itself doesn't involve the concept of academic years although it is used for applications under certain academic year). So I have no doubts in believing the 6745 applicants are accurate number of people applying Canada's law schools for this year as of now subject to following terms (as copied from the LSAT):
• These data are displayed by Academic Year, which is the same as the law school enrollment year. For example, academic year 2018 or 2018-2019 would indicate the academic year beginning in the fall of 2018 and extending into spring 2019.
• The Current Volume data tables include applicants for all academic terms. Current Volume reports published before 2018 summarized applicants for the fall term only and are not comparable to these new volume reports.
• ABA data reflect applicants and applications for ABA-approved law schools.
• Deferrals are not included in either the ABA or Canadian data. Deferrals are defined as "applicants admitted for a prior term who were granted a postponed enrollment to the current term."
• Please note as defined in this report, an applicant is a candidate who submits one or more applications for any academic term.
• The data for this report are updated every evening and will reflect current volumes as of that time.
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