There is. On the landing page for each cruise, there is a banner showing the things included in the cruise fare, like private executive transfers, economy class flights, etc. If you click on a category, more detail is provided. With the transfers and flights, information is provided as to what discount is offered if one does not use this amenity. At random, I checked a cruise that was Hong Kong round-trip. There was a $100 saving per passenger for not using the transfer to the home airport and a $1500 per passenger discount for not using the air. This was all on the US site for Silversea.