How do you detach the blade from the arm hinge ? (I want to swap left blade for right because the former leaves annoying thin water line at far right edge ( in middle of windshield) when turned off . ) TIA.

You usually have to push it backwards and then pull it straight down to take it off then the wiper blade slides out.

Do you guys have equal length ( 550mm/21.65" ) blades like me or L 550mm and R 580mm/22.83 " ? Is 2005.5/2006 S4 manual wrong or did factory wiper install guy make mistake on my car ?

...otherwise.