I understand that icing can occur at either the venturi or at the
throttle plate. The two are close together so there will b e some
interplay, and there is some additional fuel delivery thru the idle
ports adjacent to the throttle plate. It does explain that there are
some differences in icing situations.

Here in Minnesota, I had a Fairlane V8 that iced very badly almost 40
years ago. I know the ice was on the two venturiis when I took off
the air cleaner. They were almost totally choked off.

Do you teach leaning for max power (or better yet still leaner for max
EGT) under severe ice situations? I'm impressed that you teach the
effect of carb heat on mixture.