I know Amy led in one of the early rounds where the women were kicking butt (episode 2 or 3). She may not have led again until the final 4 or 5, though, I know Bill led 3-4 times overall, Kwame led 3 times (though that includes the finale), the Italian girl had led twice before she was booted midway through, and Katrina led twice before she was booted in 6th place (and wasn't even booted on a task she led). I think a lot of people that season were eliminated before they were ever PM, so the remaining people never had to cycle through them.