Notice the last sentence in Sach's statement. In that one Sachs clearly indicates that the idea in the first part of the paragraph is wrong. I don't really understand the explanation he gives in the final sentence. But whatever it says we can still expect the traveling twin to age less than the stay at home twin. It will take a bit of thought and investigation for me to figure out just how that works.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.