You still need to fix the issue with the jiggling tiles that occurs after they wrap fromthe bottom to the top. You are setting the 6 coord to an absolute value instead of subtracting a screen's worth of tiles so that it retains any fractional values after the decimal point, this should stop the jiggling on the "recycled" tiles.
thanks Grey. i don't understand very well what's you're talking. Coz : my bad english :-< Need to find someone to translate your sentences into french language. But many thanks to post here your fix idea.