In the 1910 case of Hills & Company, Limited v. Hoover, the United States Supreme Court dealt with a dispute over customs duties. The plaintiff, Hills & Company imported iron ore into the US and claimed that they were wrongly charged for duty under an incorrect classification by customs officials. They argued that their product should have been classified as 'iron ore' which had lower rates than what was applied - 'manganese ore'. However, both lower courts ruled in favor of the government's classification and dismissed Hill's claim. The Supreme Court affirmed these decisions stating that while it is true there are traces of manganese in all iron ores; this does not make them manganese ores within tariff laws unless manganese is present to such an extent as to give them a distinct commercial identity as such. In this case, evidence showed that despite having some amount of manganese content (around 12%), it did not change its commercial identity from being iron ore because it was bought and sold on market primarily for its iron content rather than any other element contained therein.

In the dissenting opinion for Hills & Company, Limited v. Hoover, it was argued that the majority's decision to uphold a tax on imported goods based on their value at the time of exportation rather than upon arrival in America contradicted previous court rulings and legal principles. The dissent emphasized that this interpretation could lead to unjust taxation as it did not account for potential changes in market conditions during transit which might decrease or increase an item's worth. It also pointed out that such a ruling would create uncertainty and unpredictability in international trade due to fluctuating values of goods between departure and arrival times. Furthermore, they contended that this approach disregarded established customs laws which traditionally assessed duties based on import values at destination ports instead of foreign points of origin.