Earlier quoted context omitted.
True, but that's like saying a British person wouldn't be confused by the phrase "the trunk of my car" said by an American even if they would would say "the boot of my car" themselves. The fact still remains than "trunk" is US dialect and "boot" is British, and that the dialects are different.
Shouldn't that comparison be weighted by how frequent the words are? For example words in the top 100 usage would count for more than the top 1000 and the top 10000. It would be a much different story if British English and American English had different words for "a car". Which, by the way, happens in Spanish dialects ("el coche" vs "el carro").
* auto: car
* coche: stroller or carriage (depending on context)
* carro: cart or carriage (see above)