Yep. I can see the dilemma. I have just been thinking about it myself, and here is my attempt to analyze and reconcile the seemingly conflicting or ambiguous requirements.
1. CEO/CIO interview says the following: flat prices per destination and per class.
2. But the Use Case to Price Itinerary says the following: price each segment of the itinerary and add the prices together to come up with the cost.
These two conflict! The problem I think is the imprecise vernacular used by the two sources of information. Number one says 'destination' and number two 'segment'. I tell you the way functional requirements are elicited is more an art than a science and almost always requires many follow-ups... which we cannot do here. Myself, I am going to assume in my analysis that the CEO really meant to say 'segment' when he blurted out 'destination'. My feeling is that the use case documentation (number 2) is slightly more strict and trumps the interview which seems to me a rather loosy-goosy single exchange... I would also think that the "Business Analyst" (presumably a specialist in the field) must have done many of such interviews before writing the use case, so it should be more accurate.
To sum up, I assume that each segment indeed has a flat price, but not necessarily the final destinations (unless it comprises just one segment). Without making this assumption, I cannot see how I can submit the part II -- and I really would like to do that.
Let me know if my thinking makes sense to you, or not.