Refunds are based on the date of withdrawal from the session, not a course, as per the relevant refund schedule on the Student Accounts website.
The date by which the Registrar's Office receives written notification of withdrawal from the session is used to determine fee charges for the session/year (if any).
Please note that the last day to cancel a course or registration with no academic penalty is not the same as the last day to be eligible for a refund.
Also, U of T graduate programs charge a program fee, not a course fee. Fees are charged based on registration in a session, either full-time or part-time, in those programs that allow part-time registration. Therefore, dropping courses without notifying the Registrar's Office to cancel your registration or change your registration status (full-time, part-time) will not result in any refund.