Structure of Price Elements
All total prices will be kept together in a Prices/TotalPrices block in the BookingResponse (String_booking.xsd). To be decided: Use a central block for detail prices as well which will the contain an ID reference to the services / travellers they refer to, or keep them with their respective elements.
The same question arises for the "requested prices" in the BookingRequest - keep them in a central place or with the services they relate to.
TODO: Define the workflow from prices returned by a search or given by external systems to prices from booking availability.