Imperial Tobacco Division of Imasco Ltd. v. Deputy Minister of National Revenue (1986), 13 CER 13, aff'd (1988), 18 CER 10 (FCA)
Between the time that the applicant presented an import entry for the importation of tobacco at the Port of Montreal, and the time that the tobacco was taken out of the customs warehouse in keeping with the normal practice, the rate of excise taxes was increased.
In finding that the lower rate of duty applied, the Board found that the goods were imported into Canada at the time when the applicant became liable for payment of the taxes, which occurred upon the entry of the goods (the filing of the B-3 form with Customs).
Canada Sugar Refining Co. Ltd. v. The Queen,  AC 735 (PC)
Given that the Customs Tariff Act, 1894 provided that duty was payable when goods were imported into Canada, it followed that it was intended that the time referred to was when the vessel in question entered the port of discharge rather than a Canadian port of call along the way to the port of discharge.
The Appellant was found to be subject to duty on the importation of sugar, which was imposed on importations that occurred after the time it did an interim reporting at the port of call (in Halifax) but before it reached the port of discharge (Montreal). In the case of goods that would not be discharged at a port of entry, it was noted that the time importation would be when they were brought within the limits of Canada.