Documentation relating to my Ixus 900 Ti states that the lens zoom range is (35mm equivalent): 37-111mm. When I use my Ixus 900 Ti the zoom displayed on screen says 22mm at the wide end and 70mm at the telephoto end (35mm equiv).
It seems the conversion isn't set up correctly in this port. To fix this, we need to know the number of zoom steps, and the real (not 35mm equiv) zoom at each step.
I think an old camera like this will only have a few steps, if it has more than 10 don't bother trying to list them all, we'll need a different approach.
You can get the real FL value by shooting and looking at the exif. (edit: I said to use misc value before, but those values are wrong)