Landed cost is a stack, and the stack is the same every time: product cost, freight, insurance, duties, taxes, port and handling charges, broker fees, and currency and financing costs. The per-unit landed cost is the total divided by the units, and the per-unit number is the one that decides whether the product makes money. A quote that gives you a total without the lines is not a quote. It is a guess, and the guess is usually low.
Freight is the line that moves most. Check it against the rate sheet, and check whether it is the rate for the service quoted or the rate for the service you will actually get. A quote that prices ocean freight and delivers air freight is a quote that is wrong by a factor of five. Insurance is the line that gets skipped most often. It is usually calculated as the goods plus freight, times 1.10, times the rate, and a quote that omits it is a quote that leaves you uninsured, which is a different kind of cost.
Duty is the line that requires the most checking, because it is the line where the quote has the most room to be wrong. Check the HTS number first: a wrong code means a wrong rate, and a wrong rate means a wrong duty. Then check the rate itself, against the rate in effect on the entry date, not the rate in effect when the quote was written. Section 301 and Section 232 duties stack on top of the MFN rate, and a quote that models only the MFN rate is a quote that is missing the largest part of the duty.
The merchandise processing fee is the line that gets miscalculated most often. It runs 0.3464 percent of the customs value, and a quote that applies it to the wrong value, or applies it twice, or omits it entirely, is a quote that is wrong by a small amount on every unit, which is a large amount on a full container. Check the MPF, check the harbor maintenance fee, and check the broker fee against the broker's published schedule, because a broker fee that is not in the quote is a broker fee you will pay anyway.
The quote that looks cheap is usually missing a line, not beating the market. The lines that go missing most often are the port charges: the terminal handling charge, the chassis fee, the demurrage and detention that accrue when the container sits, and the drayage from the port to the warehouse. A quote that prices the freight to the port and stops there is a quote that leaves the most expensive part of the journey out of the number.
Run the audit the same way every time: check each line against its source, check the total against the lines, and check the per-unit number against the selling price. If the per-unit landed cost leaves less margin than you need, the product does not make money at that price, and the answer is to change the price, change the supplier, or change the product, not to argue with the arithmetic. For the port charges that follow the quote, freight surcharges and the gap between quote and invoice covers the fees that appear after the quote, and DDP versus DAP and who pays the duty explains the term that decides which lines are yours.
The full cost of getting a product to your warehouse: product cost plus freight, insurance, duties, taxes, port and handling charges, broker fees, and currency and financing costs, divided by the units. The per-unit number is the one that decides whether the product makes money.
Check each line against its source: freight against the rate sheet, duty against the HTS number and the rate in effect on the entry date, and the MPF at 0.3464 percent of customs value. Then check the total against the lines, and look for the lines that are missing entirely.
The MPF runs 0.3464 percent of the customs value on a formal entry. It is the line that gets miscalculated most often, applied to the wrong value, applied twice, or omitted entirely.
Usually because a line is missing, not because the supplier is cheaper. The lines that go missing most often are the port charges: terminal handling, chassis, demurrage and detention, and drayage from the port to the warehouse.