“The most comprehensive analysis of the issue in our court appears to be the decision of Mackinnon J. in Gauthier v. Hart, where the court conducted an extensive review of the authorities, including the decision in Chickee and the other cases referenced above from Saskatchewan and Nova Scotia, and concluded that the more appropriate interpretation of s. 9 requires a calculation of time over a calendar year: 2011 ONSC 815 (CanLII) at 65-76. The decision in Gauthier was adopted in Thompson v. Thompson, where Chappel J. observed that “it has been held that the appropriate time for the calculation of time spent with each parent is the calendar year.”: 2013 ONSC 5500 (CanLII) at 40.
While I acknowledge that the language of s. 9 is, arguably, capable of supporting more than one interpretation, in my view, the better interpretation is to read s. 9 as requiring a calculation that demonstrates whether the parent had the child for not less than 40 per cent of the time over the course of a calendar year, as Mackinnon J. concluded in Gauthier and Chappel J. concluded in Thompson.
In my view, such an interpretation more closely accords with the text of the language of the Guidelines, which, it is worth noting, does not say “for not less than 40 per cent of the time over the course of any contiguous 12-month period.” If Parliament had intended to permit “any 12-month period,” it could have expressly said so.”