... while NBC officially said no final decision on the plan had been made, two senior NBC executives who had talked to the top management about the moves said that under the plan being discussed, Mr. Leno would definitely shift back to 11:35 but in a half-hour format, while Mr. O’Brien would slide back his start time by a half hour and then produce an hourlong show."Late Night With Jimmy Fallon" would move to 1:07 a.m., according to the Times. "Tonight's" start time has changed before: it began at 11:15 p.m. on Jan. 7, 1957, moved to 11:30 p.m. on Jan. 2, 1967, then moved again to 11:35 p.m. on Sept. 2, 1991. Having "The Tonight Show" sign off at around 1 a.m. each morning is nothing new for NBC. "Tonight" ended at 1 a.m. from Sept. 27, 1954 to Oct. 5, 1956, and again from Jan. 7, 1957 to Sept. 5, 1980. A recent statement from the network acknowleges the low-rated "Leno Show" has preicipitated "issues" with NBC affiliates, many of which have seen their post-"Leno" ratings plummet. New episodes of "Leno" are routinely pwned at 10 p.m. by repeats and basic cable fare. NBC execs had anticipated new episodes of "Leno" would perform better when competing against repeats on CBS and ABC; this has not proven the case. The O'Brien-led "Tonight Show" and the rest of NBC's late line-up have also performed much more weakly since "Leno's" primetime numbers began falling. In a Business Week interview posted New Year's Eve, NBC primetime entertainment president Angela Bromstad indicated the network plans to increase production of new shows to the most since 2003, another hint perhaps that the Leno experiment is ending. On Tuesday, NBC's "The Biggest Loser" enjoyed its biggest premiere ever with a 4.6 rating in 18-49. The "Leno" episode that followed scored only a 2.2 in the same demo. On Wednesday, a 9 p.m. episode of NBC's "Law & Order SVU" hit a new season high of 3.2 in 18-49. "Leno" followed it with a 1.5. "Leno's" numbers have fallen so far since its late-summer premiere, one wonders if repeats of "Law & Order SVU" and "The Office" couldn't perhaps garner better ratings (and at a considerably lower cost) in the 10 p.m. hour than new episodes of "Leno."