On a TV show, the guests are shown 5 people and are listened to them with a short sentence, who could sound as UK or US accents, and the guests are expect to guess where they really are from. One of the people seemed like a American but sounded very British and the guest told him:
I WAS TOTALLY OFF ON YOU. UK or US (see:3:50-3:55)
What does this mean? Does it mean I was sure about you?