I sometimes go for 6th also but it is not needed at all. I agree 5th is more flexible and can be used for anything from 40 through wide open. I think we would miss the extra punch when passing at highway speeds that 5th can offer over a 6th highway gear. I love the acceleration that 5th has and I think it is a safety issue for instant lane positioning without downshifting.
Steve

People think I am joking but I believe (know) it is truly a safety issue not to have all the power we need!!!