From the comments:

2A and 6B are the same too. Maybe the repeats got the best results in the first five sets of trials so they brought them back and pitted them against each other as well as the traditional rotary phone number arrangement in round six. 6A eventually won, obviously.

These were tests. They tested each group against each other, so some of the patterns were tested more than once.

Maybe. It looks like the buttons are a bit smaller with slightly more space between them.