You just do not understand how the finances of that time period worked. 75% of everything exported was Southern Agriculture products. The import equation must balance, and it cannot balance unless you acknowledge that the biggest chunk of that import money/goods/services was paid for by those exports.
The record keeping is irrelevant, the place where the tariff's were collected is irrelevant, the only thing that matters is that Southern Products were most of what was being sold to Europe, and therefore most of the money earned from Europe was the consequence of those same products.
Again, tariffs are put on foreign exporters, not a nation's own exporters. lol