Naval architects have been playing with sheer lines for many years. Sheer plays a very important part, not only in the look of the boat, but the overall scale of the vessel as well.
1rst Photo A stepped sheer is used to add about 4-5 more inches to the forward cabin roof without destroying the overall scale of the boat. You see this trait quite often in expedition boats. It provides for a higher bow as well.
2nd photo A false sheer is used to allow a higher salon where if the rub rail was at the actual toe rail, the boat's scale would be destroyed. Over the years, Silverton (and many others) have used this design feature quite successfully.