8. (1) In this section, “adjustment date” means January 1, April 1, July 1 or October 1; “average prime rate”, on a particular date, means the mean, rounded to the nearest whole percentage point, of the annual rates of interest announced by each of the Royal Bank of Canada, The Bank of Nova Scotia, the Canadian Imperial Bank of Commerce, the Bank of Montreal and The Toronto-Dominion Bank to be its prime or reference rate of interest in effect on that date for determining interest rates on Canadian dollar commercial loans by that bank in Canada.  O. Reg. 309/97, s. 1. (1.1) For the purposes of the Act, the prescribed rates of interest shall be determined in accordance with the following rules: 1. A base rate of interest shall be determined for January 1, 1997 and for each adjustment date after January 1, 1997 and shall be equal to the average prime rate on, i. October 15 of the previous year, if the adjustment date is January 1, ii. January 15 of the same year, if the adjustment date is April 1, iii. April 15 of the same year, if the adjustment date is July 1, and iv. July 15 of the same year, if the adjustment date is October 1. 2. The base rate of interest in effect on a particular date shall be, i. the base rate for the particular date, if the particular date is an adjustment date, and ii. the base rate for the last adjustment date before the particular date, otherwise. 3. The prescribed rate of interest payable by a person under the Act in respect of a particular day shall be an annual interest rate that is three percentage points higher than the base rate of interest in effect on that day. 4. The prescribed rate of interest to be paid or allowed by the Minister to a person under the Act, in respect of a particular day before July 1, 2006, shall be an annual interest rate that is two percentage points lower than the base rate of interest in effect for that day. 4.1 The prescribed rate of interest to be paid or allowed by the Minister to a person under the Act, in respect of a particular day after June 30, 2006, shall be an annual interest rate that is three percentage points lower than the base rate of interest in effect for that day. 5. For an overpayment that results from a decision of the Minister or a court on an objection to, or an appeal from, an assessment or a statement of disallowance, the prescribed rate of interest to be paid or allowed by the Minister in respect of a particular day after December 31, 1998 is the base rate of interest in effect for that day.  O. Reg. 309/97, s. 1; O. Reg. 451/99, s. 1 (1); O. Reg. 222/06, s. 1. (1.2) Revoked:  O. Reg. 309/97, s. 1. (2) On the amount of any refund made under subsection 13 (1) of Regulation 464 of the Revised Regulations of Ontario, 1990, interest shall be paid, calculated from the date of application to the Minister for the amount to be refunded to the date when the refund is made or is applied by the Minister against other liability of the person entitled to the refund.  O. Reg. 179/96, s. 3 (1). (3) Interest is payable on the amount of any overpayment refunded under subsection 21 (6) of the Act or applied under subsection 21 (8) of the Act, calculated as follows: 1. If the overpayment results from the transmittal or payment to the Minister of an amount in excess of the amount required, interest is calculated from the date of application to the Minister for the refund of the overpayment to the date the overpayment is refunded or is applied by the Minister against any other liability of the person who is entitled to the refund. 2. If the overpayment results from a decision of the Minister or a court on an objection to, or an appeal from, an assessment or a statement of disallowance made under the Act, interest is calculated from the date the overpayment was transmitted or paid to the Minister to the date the overpayment is refunded or is applied by the Minister against any other liability of the person who is entitled to the refund.  O. Reg. 451/99, s. 1 (2). (4), (5) Revoked:  O. Reg. 309/97, s. 1. (6) Interest accruing after December 31, 1994 on any refund made under the Act or the regulations shall be computed and compounded daily.  O. Reg. 179/96, s. 3 (3).