But I think there was a max of 3 in any season. So if you had only a single TV game one year, you couldn't have 4 the next year. Of course, ND always had either 2 or 3 per year.
ND had only two TV games in its 1977 NC season -- at Pitt and vs. USC. The most attractive game that year not on TV was at Clemson. So that meant ND had an allotment of 3 in 1978, and then 2 again in 1979 (at Michigan and vs. USC).
1980 was another 3-TV-game season. ABC decided to move the Purdue game from Sept. 27 to Sept. 6 and nationally televise it, and also moved the USC game from Nov. 29 to Dec. 6. With our first-ever trip to Alabama in November an obvious TV choice, this meant the Michigan game was not televised -- the only time since the 1978 renewal of the series that has happened. It turned out to be the best game of the entire series, with Harry Oliver winning it on the miraculous 51-yard field goal.