Does PST apply if vehicles have an international licence and, if so, is the calculation different?
Yes. If your vehicle is used interjurisdictionally for commercially transporting goods or passengers and it is licensed under a pro-rating agreement, you will pay multi-jurisdictional vehicle (MJV) tax upon licensing with your home jurisdiction. However, the calculation is different. Please see Bulletin SST 073, Multi-Jurisdictional Vehicles for details on the formula.