Unfortunately for the OP, jsm0085 is correct, even if s/he explains it differently.
CIC does not "restrict" overtime hours, but before Jan 2, 2013, defined full-time employment as "at least 37.5 hours per week." Any week that meets or exceeds 37.5 hours is one full-time week. A week in which you worked 40 hours per week is one full-time week. A week in which you worked 65 hours per week is one full-time week. Period. For full-time weeks, you don't count hours, it is just one full-time week.
You only count hours if you work part-time (e.g. fewer than 37.5 hours), so that you can calculate the full-time equivalent.
If the OP tried to mix actual full-time hours with part-time hours, that would be a mistake. The only way you could do that is if you counted each full-time week as 37.5 hours (you would have to ignore any hours worked past that). This is why jsm0085 calls it a "limit."
For example, you work for 2 weeks. One week you work 45 hours, one week you work 30 - so one week is full-time, one week is part-time The WRONG way to count this is to add the two weeks together (75 hours) and average them at 37.5 hours per week. This now looks like you worked 2 full-time weeks, which is not correct. You have worked 1.9 full-time weeks. Over 2 years, this makes a difference. For example, if you extend this same pattern over 2 years, you've worked the full-time equivalent of 98.8 weeks instead of 104. So you have not met the 2 year work requirement, you are short by 5-6 weeks.
This is why some of us try to urge applicants NOT to apply immediately as soon as they think they qualify, but to have patience and wait a little bit, in case of a miscalcuation. It really sucks to be refused when you're short by a couple of weeks. Remember, the 1 year or (then, 2 year) requirement is a MINIMUM requirement. Give yourself some extra time before applying.