Demetris said:To the point. At least on HS carbs, where everything is easily visible, there is some built-in lost motion (i can't think of a better description at the moment) in the lever that lowers the jet.
My original posting was aimed at HIF6's, but I can't really disagree with your summing up of HS6's, it just proves my point that you've already got lost motion in the linkages before you even start to think of the amount that builds up through normal wear and tear, which is why however hard you try with them, they're always going out of tune.