X-Factor Polling

Apparently the twins John and Edward polled the highest vote at the weekend despite the fact that they are rubbish singers. Some see it as an anti-Simon Cowell vote. Well, naturally I was surprised that Miss Frank group went out. They were good. But I didn't vote. I might have voted if I could vote for an act to leave the contest. Somehow I don't think that idea would get off the ground.
But the voting system is wrong. The acts that leave should be the ones that have polled the lowest number of votes over ALL the weeks they have been on the live programme. It shouldn't be the ones that score the lowest in a particular week.