Loma,
So would I, it goes against logic. I would expect a larger frontal area to catch more ice - and faster, but apparently the opposite is true.
I remember seeing a photograph of a camp either at the N pole or up a mountain somewhere. The guy ropes on the flagpole had inches of ice on them yet the flagpole which was much thicker had none!
Bringing it back to aircraft, the early 737-3/400's had a sharp pointed spinner on the engines. It was soon discovered that these picked up a lot of ice which shed into the engine so they made the spinner round instead.
S & L