Fox Broadcasting Co. will go to a regular seven nights of programming beginning June 21, when its “Fox Night at the Movies” slot will become a weekly entry on the weblet.The move, which fulfills a mandate by Fox Inc. chief Rupert Murdoch, will bring Fox up to 16 hours of regular programming each week (four on Sunday and two every other night), compared to 22 hours by each of the Big Three networks. Because of current Federal Communications Commission rules that define a network as any service providing more than 15 hours a week of prime time programming on a national basis, Fox will have a choice: either drop an hour of regular programming (most likely on Sunday from 10-11 p.m.) or air the movie on a biweekly basis. Fox will have six months to comply with FCC guidelines once it has averaged more than 15 hours of programming per week over a month, meaning the weblet won’t have to make a final decision until 1994. A spokeswoman said Fox will put off a solution until closer to that date, barring changes in the financial interest and syndication rules that would render the point moot. Assuming the fin-syn rules remain unchanged, Fox has ample incentive to cap its programming at 15 hours per week, since the alternative would make the program service subject to the same restrictions as the Big Three webs, who are constrained in terms of their ability to share in back-end revenue from shows they produce. By contrast, Fox also operates an extremely profitable syndication arm, Twentieth TV, which distributes such first-run shows as “A Current Affair” and “Studs” in addition to off-network properties “MASH,”"Batman” and “The Simpsons.” The goal of a nightly schedule has been achieved in less than six years. Fox started with two nights of prime time programming in April 1987 and has gradually expanded, adding its fifth and sixth regular nights, Wednesday in June ’92 and Tuesday last month. “Fox Night at the Movies” will consist of theatricals and made-for-TV movies produced under the aegis of Fox West Pictures, a Fox Inc. subsidiary put in charge of that area. Until then Fox will continue to air movies on a monthly basis, with “Licence to Kill” to air Wednesday, “Betrayed” on March 15 and “Young Guns,” repeating April 12. Fox West recently announced a half-dozen TV movies in production to begin airing this spring (Daily Variety, Dec. 17, 1992).