I think the Super Ikontas were aimed at the travelling professional. At the time, the lens and build were really quite stunning. They weren't really cheap either when you compare them to other folders at the time (see: Kodak).
I'm interested in seeing your test rolls. It sounds like there's enough of us folder enthusiast here to get this riddle solved. Film tight, lens parallel to film, shot the same shot at f/8 and f/22 and see if that helps.
Enjoy! I dearly miss mine =/