This is probably dumb, but it's not clear to me from the wording what happens if you have, say, 10 A, 10 B, 9 C, where A, B, and C are all Action cards. Presumably the 'tie' refers to tie for 2nd, so it sounds like A and B would not count.
Edit: Come to think of it, it's not clear to me what happens when you have a deck consisting only of 10 A, 10 B, where A and B are both Actions. Are the both the first and second most common Action, or only the first?