When in doubt, blame your agent. I'd be surprised, too, if I bought Cushman's argument. His reasoning, however, is a mess: --Cushman claims the Nielsen ratings were super-secret (this is quite overstated). --Although he presents Nielsen ratings for almost every broadcast of the series on NBC (I believe the initial run of 'Where No Man Has Gone Before' is omitted) there is very little information about how the series ratings compare to the rest of television in general (in other words, the numbers that informed ad rates). --The ratings presented in the book are a mix of two different figures: those measured in twelve major markets and those measured nationally. The former, more limited sample is weighted towards the audience that watched Star Trek. The broader, national figures show a smaller audience for the series. --The book repeatedly refers to Trendex with Nielsen as being the same (Trendex, Nielsen, and Arbitron were the three major competitors when it came to measuring ratings in the 1960s).