I think "exceeded expected" is a bit of marketing speak here. Did the sales really exceed what they expected? If so, they must be pretty bad at forecasting how much of their own stock they sell, time and time again.

And if the 5C was one of the models that exceeded expected sales, why would they be notifying their suppliers of cuts? Wouldn't they be saying "Good news, sales are better than we thought".

The exceeded expectations is completely meaningless. It clearly didn't.