The translation into American English is wrong. It should say: two tonnes, not two tons. 1 ton in American English is 2000 lbs but 1 tonne is 1000 kilos or 2200 lbs. Because USA is not metric you must distinguish between the 2 types of "tons". When you translate "τόνοι" to English, it should always be "tonnes" because Greece is metric.
It's the metric tonne=1000 kg. Greeks never use British imperial tons or short tons (actually, being a greek myself i had to google it, i was not even aware of their existance) so no specific word exists in greek. If i had to specify it for some (unexpected) reason, i would say "αγγλικός/βρετανικός τόνος or τόνος στο βρετανικό σύστημα" "αμερικανικός τόνος or τόνος στο αμερικάνικο σύστημα".