(1)  A provision in a retail lease that specifies that the rent is to be determined either fully or partly by reference to the turnover in relation to the retail premises is void unless the lease specifies how the rent is to be so determined.

(2)  For the purposes of any provision of a retail lease that relates to the determination of rent or a component of rent by reference to the turnover in relation to the retail premises, turnover does not include any of the following items:

(a) any loss incurred in the resale or disposal of goods reasonably and properly purchased from a customer as a trade-in in the usual course of business;

(b) any deposit or instalment received on account of a lay-by, hire-purchase or credit sale which is refunded to a customer;

(c) any payment for merchandise or services that is refunded;

(d) any services, finance or interest charge payable by the tenant to any financier in connection with provision of credit to a customer, other than a commission on credit or store cards;

(e) the exchange of merchandise between retail premises of the tenant if the exchange is made solely for the convenient operation of the business of the tenant and not for the purpose of consummating a sale made at the premises;

(f) any return to a shipper, wholesaler or manufacturer;

(g) any sale of the tenant's fixtures and fittings after their use in the conduct of the business at the premises;

(h) any discount allowed to customers in the normal course of business;

(i) any uncollected credit account that is written off;

(j) any purchase tax, receipt tax or other similar tax imposed on the purchase price or cost of hire of merchandise or services at the point of sale or hire;

(k) any sale of lottery tickets or similar tickets other than commissions.

(3)  A landlord may require that the turnover figures provided by a tenant be audited.

(4)  A landlord is to keep the turnover figures provided by a tenant confidential.