Canadiandesi2006:
You can easily run the scenario through the online physical presence calculator and confirm.
And yes, it will confirm that four years plus a day after landing will meet the qualification so long as, of course, the PR did not leave Canada at all (thus was physically present for 1460 days as a PR).
Thus, as others have noted, the PR who landed August 1, 2012, and who remains in Canada without leaving, will be eligible to apply August 2, 2016. (In this scenario, this applicant will also meet the 183 days X 4CY requirement based on 183+ days presence in 2013, 2014, 2015, and 2016.)
Sure, the relevant time period for calculating presence is still six years, but the fact that some or almost two years of the time absent predates the date of landing does not matter.
The website describes it this way: "To qualify [the applicant] must have, since becoming a permanent resident, been physically present in Canada for at least 1460 days in the six (6) years immediately before [applying]."
Note: a person who has been present in Canada without leaving four years plus a day since becoming a PR has, in simple arithmetic, been in Canada 1460 days within the preceding six years.
By the way; regarding margin over the minimum:
While the applicant who never leaves may opt to apply with a small margin, for applicants with any significant number of absences, or any absences of significant duration, a good margin over the minimum is the prudent approach. Hard to suggest a number. A month or three seems prudent to me, longer in some circumstances.
