The book IS correct. From personal experience descending from about FL60 a few years ago in a Bulldog. I had a cold starting that I didn't know about, (symptoms appeared the next day), and had a piercing pain start in my sinuses as we passed 2000' descending to circuit height. So painful, in fact, that I was unable to concentrate on flying, and my instructor took over. He was concerned enough that he declared an emergency and had an ambulance meet us on landing, after a very gentle descent.
I certainly wouldn't risk flying with a cold now.