When you’re at the top the only place to go is down, or at least that’s what media researchers think Fox will figure out tonight when it premieres “The Next Joe Millionaire: An International Affair.”
   With only a modest twist on the premise of the original “Joe Millionaire”--in which women were duped into thinking a potential mate was loaded--most media people think the audience for “The Next Joe Millionaire” will be off roughly 5 to 20 percent from the first version.
   That’s not a major drop for Fox, since the show was a distant No. 1 last season in the 18-49 demographic. But most media researchers contacted by Media Life think the huge audience the show pulled last time was a one-shot deal.
  “I think the sampling could be there, but if there isn’t enough of a hook to reel them in it could drop down quickly,” says Shari Anne Brill, vice president and director of programming at Carat.
   “I wouldn’t be surprised if it started out at 20 million viewers because of curiosity. It just might not hold them after that.”
   As media people are quick to point out, “The Next Joe Millionaire” isn’t expected to be a bomb. More likely it will pull decent ratings. But in comparison to the first version it may look like a disappointment.
  The original “Joe” had a run that would be hard to top.
   Its season finale was the most-watched entertainment show last season with 40 million people tuning in. It averaged 20 million viewers for regular episodes, not counting the finale, and captured roughly 25 percent of the available female 18-49 audience and 20 percent of the male 18-49 audience when it was on.
   The problem for “Next Joe,” as it became clear even before “Joe” finished its run, is that the premise that made the original so compelling is no longer novel. “Next Joe” still dupes women into thinking the guy is rich.
   To keep it fresh “Next Joe” is set in Italy with 14 women from Europe who are unaware of the first version’s twist. They will vie for the affection of David Smith, a Texas cowboy.
   “Knowing Mike Darnell (Fox’s executive vice president of alternative programming), there has to be another twist,” says Laura Caraccioli, vice president and director of SMG Entertainment.
   “This might be the first way to get us involved in the show. It’s hard to imagine it doing the same numbers as it did the first time, but it depends on how they plan on laying out this show.”
   If the European women are the sole twist, it’s unlikely to be enough to captivate viewers.
   “I think the other problem is that viewers were inundated with reality all summer and they are desensitized to a lot of it,” says Roy Rothstein, vice president and director of national broadcast research at Zenith Media.
  “I’m not saying it will be a failure but I’m saying it will not be as strong as it was.”
  “Next Joe” has a few other obstacles.
   Perhaps the biggest of those is its new time slot. Although still on Mondays – with a second original on Tuesdays – it is moving from 9 p.m. to 8 p.m.
   “They are moving it up a full hour, which has slightly lower viewing levels,” says Jordan Breslow, manager of national broadcast research at MediaCom.
   “So I think it will have some fatigue to it, but I think the numbers will be fairly consistent with how they’ve been. It seems to me the only place to go is down, although I think Fox has something on its hands there.”
   “Next Joe” also has tough competitors in NBC’s “Fear Factor,” CBS’s comedies and the WB’s “Seventh Heaven.” On Tuesday it will face the return of ABC’s “8 Simple Rules” on Nov. 4, when the show will resume without the late John Ritter.
   Another problem for “Next Joe” is that hit reality shows tend to slip after the original version. The exceptions include Fox’s “American Idol” and few others.
   “Each network tends to have one or two shows that work for them,” says Breslow. “‘Joe’ is a formula that should work again, but personally I don’t think the ratings will be as high.”