Springchicken, here is what the mod posted on the Big Fish forums about this:
We will not be issuing refunds for those upgrading to the Collector's Edition at the sale price. However if you already purchased a Collector's Edition at the sale price to upgrade from the standard version, please contact Customer Support so that they can issue a refund for the Collector's Edition if you are no longer interested.
Big Fish is handling upgrades differently only in regard to this CE sale.