Yeah you tried it. Didn't make sense then, doesn't make sense now. But the short answer is that at the end of the day the consumer pays the 15% through a markup on the item sold. But why was it sold to a New York diamond merchant? Because that's where the demand is. That's where the importer is who buys the raw material and makes the ring. He then sells it into his supply chain. But for William's scenario to be true and your scenarion to make the point you want to make, we would have to live in a world where 75% of the diamond merchants live and work in Charleston and the diamond is still imported through New York where it is landed, taxed, and then sent to Charleston for delivery to the diamond merchant.
After complaining that my question did not make sense, you actually answered it correctly.
The point of the question was to establish the difference between point of entrance into the US and point of consumption.
Sometimes the importer paid the tariff on entrance into New York....sometimes he did not. The federal rules allowed the importer to wait up to three years to pay.
And as you also correctly pointed out, the tariff amount was passed on down the line to the end consumer as part of the product cost.
Let it finally be said that data on tariff collection by the Treasury only shows where the money was collected on imports, and not where the eventual consumer resided.