I attended the visit day of U of T on Feb. 12 and 13. They sent a series of acceptances a week later (Feb 16th and 17th). I talked with several faculties there and they told me that there will be three round of acceptances. One was Feb. 16th and 17th, the other on March 9th and 10th and the last one will be around April 1st. They also told me that according the ECE recent decision the RA that a faculty should pay to an international student has increased a lot (because the university doesn't pay the difference between international and domestic tuition any more) and right now an international student costs them 2.5 times a domestic one and therefore the chance for an int. student to get in is very very small.
I think the reason for extending the deadline is to receive more domestic applicants and try to somehow compensate for the loss they will undergo by not taking high quality int. applicants.