Networks Delay Schedule Changes : Entertainment: An ad slump is behind the stand-pat approach: Advertisers may withdraw when shifts are made.

The three television networks, facing one of the worst advertising slumps in a decade, are delaying changes in their prime-time program schedules in order not to risk losing tens of millions of dollars in badly needed revenue.

Since the networks unveiled their new shows in September, only a handful of program changes have been made. This reverses the trend of recent seasons, when the networks would not hesitate to make wholesale schedule changes within weeks of a show’s first broadcast.

Driving this stand-pat approach on programming is an anemic fourth-quarter advertising marketplace that has all three networks discounting ad time to 50% or less of rates in the “up-front” market. Networks traditionally sell about three-quarters of their ad time in advance during the summer and the rest at higher rates once the new season is under way.

“Any time the schedule changes, the advertiser has the option to withdraw,” said Peter Tortorici, senior vice president of CBS Entertainment. “And in a weak marketplace, the danger is more threatening than at other times. The mandate we’ve received is to keep that in mind but also deliver the best prime-time schedule we can.”

ABC has kept its schedule fully intact, while NBC has dropped only one show--”Hull High” on Sunday nights--and reversed the order of “The Fanelli Boys” and “Dear John” on Wednesdays.

CBS, which has surprisingly moved into second place this season from third, has made only a handful of program changes, such as canceling the Saturday night series “E.A.R.T.H. Force,” moving “48 Hours” to Wednesday, shortening “Top Cops” to a half-hour and suspending “Lenny” from the schedule.

“Two of the three networks have not been making changes,” said Paul Schulman, president of his own ad-buying firm in New York. “If a show switches time periods, the advertiser has the option to stay with it or negotiate for credit. In effect, it throws money up in the air that in a soft marketplace the networks are uncertain they will keep.”

During the fourth quarter of 1989, the three networks took in a total of $2.2 billion in revenues. For prime time alone, the networks brought in $974 million, according to the Broadcast/Cable Financial Management Assn., a Chicago-based trade group. Network executives said it is doubtful that those levels will be achieved in the fourth quarter of 1990.

Warren Littlefield, president of NBC Entertainment, said replacement ads can sell for as much as 30% less than the original ads when a show changes time periods. “That’s where the pain comes in,” he said.

In previous seasons, selling replacement ads at the full rate was not much of a problem. Usually there were more sponsors wanting to buy ad time than there were spots available.

But, explained William Croasedale, executive vice president of Backer Spielvogel Bates, a New York ad agency, “we are in a recession, and networks don’t want to give advertisers the chance to snatch those dollars back.”

Ironically, the current problems may actually turn out to be beneficial because some shows will not be canceled prematurely. Now, shows might be given a longer chance to attract an audience.

“This could turn out to have a positive effect,” said Robert Iger, president of ABC Entertainment. “In a business that has gotten way too frenetic, the economic realities have created a slowdown period, and that may be good for us and the shows. The fact the business side dictates patience takes the heat off us a bit.”