The first two rounds this year have been a few days earlier than what is stated on U of A's website. Also, I thought schools have to have offered a number of acceptances equal to the class size by March 15. It doesn't seem like you should have to wait any longer than March 15, unless you are going to be rejected or waitlisted, which you would find out later.
"Notification of action by the Admissions Committee. In January 2004, the Admissions Committee will begin to take action on applicants whose files are complete. Letters of acceptance will be mailed on or about January 31, February 15 and March 15, 2004, or the first working day thereafter. Notification of alternate or rejection status is sent on or before March 31 each year."